Component of catalyst for olefin polymerization

ABSTRACT

A catalyst component for olefin polymerization, which comprises an ion-exchange layered silicate having the following features 1 and 2:  
     feature 1: in a pore size distribution curve calculated from desorption isotherm by nitrogen adsorption-desorption method, a pore diameter Dm showing a maximum peak intensity D VM  is from 60 to 200 Å; and  
     feature 2: in a pore size distribution curve calculated from desorption isotherm by nitrogen adsorption-desorption method, a pore diameter D m½ (Å) on the smaller pore size side corresponding to a ½ peak intensity of the maximum peak intensity D VM  has a relation of D m½ /D m  of at least 0.65 and less than 1, provided that the largest value is employed when there are a plurality of D m½ values.

[0001] The present invention relates to a catalyst component for olefinpolymerization, a catalyst and a process for producing polyolefin usingsaid-catalyst. Particularly, the present invention provides an olefinpolymerization catalyst having a high activity and having an ability ofstably producing polyolefin without fouling on a polymerization reactorwall and the like by using an ion-exchange layered silicate having aspecific structure. Further, the present invention provides aprepolymerization catalyst homogeneously prepolymerized, which hasexcellent powder properties and does not produce a residue of thecatalyst leading to degradation of an outer appearance of a product.

BACKGROUND ART

[0002] A metallocene catalyst for olefin polymerization comprises ametallocene complex and a cocatalyst activating the metallocene complex.As the above cocatalyst, various compounds such as methyl aluminoxane,boron type compounds or the like have been proposed. In the productionof polyolefin using a specific process, it is required to have ametallocene catalyst supported on a carrier in view of processproperties and handling properties of polymer particles producedtherefrom. Since a metallocene catalyst used by combining well knownmethyl aluminoxane and boron type compounds is often soluble in anorganic solvent, it is used by being supported on an inorganic carriersuch as silica or an organic carrier such as an organic polymer.

[0003] Also, a cocatalyst other than these cocatalysts has beenreported. EP511665 discloses an example of producing an olefin polymerby using clay or clay mineral as an olefin polymerization catalystcomponent and combining it with a metallocene catalyst. In this catalystsystem, the carrier is characterized by having a function of acocatalyst activating the metallocene catalyst. Also, it is reportedthat an olefin polymerization activity is improved by using anion-exchange layered compound treated by an acid, a salt or acombination with an acid and a salt as a catalyst component (EP683180).

[0004] On the other hand, it has been proposed to carry outprepolymerization for purposes of improving powder properties of apolymer obtained, preventing fouling of a polymerization reactor orpreventing occlusion in a line of transporting a polymer after thepolymerization reactor (JP-A-5-295022).

[0005] However, the above techniques must have been further improved,and it has been difficult to prevent production of fine polymerparticles or agglomeration of polymer particles during polymerization.Particularly, in production of a low melting point polymer, thesephenomena have been remarkably caused and there have been seriousproblems that an industrial scale production plant could not be operatedcontinuously and stably for a long time. Further, according to themethods disclosed in these publications, a polymerization activity persolid catalyst component is not always satisfactory, and development ofa catalyst satisfying both a polymerization activity and an operationstability has been demanded.

[0006] A first object of the present invention is to provide a catalystsystem producing satisfactory polymer particle properties andparticularly to provide a catalyst system satisfying both a highactivity and satisfactory polymer particle properties. Moreparticularly, in production of a low melting point polymer, it isdemanded to satisfy the above requirements.

[0007] A second object of the present invention is to provide a catalystsystem able to carry out a stable polymerization of a low melting pointpolymer. Generally, when polymerization is supported out by using thesame catalyst under the same polymerization temperature conditions,powder properties are degraded as a melting point of a polymer producedbecomes lower, and therefore there is a lower limit to a melting pointof a polymer allowable to be industrially produced. The presentinvention is to provide a catalyst system capable of lowering this lowerlimit of a melting point of a polymer allowable to be produced.

[0008] A third object of the present invention is to provide a catalysthaving a high upper limit to a polymerization temperature. Whenpolymerization is carried out by using the same catalyst under such apolymerization conditions as to produce a polymer having the samemelting point, particle properties of a polymer having a higherpolymerization temperature are degraded, and therefore there is an upperlimit to a polymerization temperature allowable to be industrially used.The present invention is to provide a catalyst system capable ofimproving this upper limit of a polymerization temperature industriallyusable.

[0009] A fourth object of the present invention is to provide aprepolymerization catalyst homogeneously prepolymerized so as to reducea residue of a catalyst leading to degradation of an outer appearance ofa product.

DISCLOSURE OF THE INVENTION

[0010] The present inventors have variously studied, and have discoveredthat the above problems can be solved by using an inorganic silicatehaving a specific structure as a catalyst component for olefinpolymerization. The present invention has been accomplished on the basisof this discovery.

[0011] That is, the present invention employs an ion-exchange layeredsilicate having the following properties as a carrier:

[0012] (a) having a specific pore size distribution; and

[0013] (b) having a carrier strength within a specific range.

[0014] Such a carrier as having these physical properties may be amaterial occurring in nature as far as having these properties (anaturally occurring material having these properties as it is has notbeen found by the present inventors up to now) or a material treated sospecifically as to have these properties.

[0015] Examples of such treatments as to provide the aimed physicalproperties include:

[0016] (a) a chemical treatment illustrated below (particularly acidtreatment) so as to be carried out under specific conditions to providea specific pore size distribution;

[0017] (b) a granulation treatment carried out under specific conditionsto provide a specific carrier strength; and

[0018] (c) a treatment with a specific organic aluminum compound. A moresatisfactory effect can be expected by combining these treatments.

[0019] Another means for achieving the above-mentioned objects of thepresent invention is to use a prepolymerization catalyst having aspecific structure for main polymerization. The specific structure meansa structure wherein active precursor sites of a metallocene catalyst areuniformly dispersed within a particle of a prepolymerization catalyst.Since the metallocene catalyst has a high polymerization activity, it isimportant to efficiently remove reaction heat generated bypolymerization. If the active precursor sites of the metallocenecatalyst are not uniformly dispersed, heat is not satisfactorily removedat the part and a temperature is locally raised. As this result, thereare caused problems that a produced polymer is dissolved in a solvent,that a produced polymer is melted or polymer particles are agglomeratedto each other and that a produced polymer is adhered to a reactor wall.

[0020] In the present invention, it has been intensively studied as tohow uniformly the active precursor sites should be dispersed in order toprevent the above-mentioned problems, and it has been discovered that itis possible to observe a dispersion state of active precursor sites of ametallocene catalyst in a particle by means of fluorescent analysis.According to the present invention, the above problems can be solved ifan index showing a uniform dispersibility (prepolymerizationhomogenization index: H-value) is within a specific range.

[0021] Examples of means for making H-value within a specific range inthe present invention include:

[0022] (a) to use an ion-exchange layered silicate having theabove-mentioned specific structure; and

[0023] (b) to use specific prepolymerization conditions. A moresatisfactory effect can be achieved by combining these operations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 illustrates a pore size distribution curve of anion-exchange layered silicate used in Example 1.

[0025]FIG. 2 illustrates a pore size distribution curve of anion-exchange layered silicate used in Example 2.

[0026]FIG. 3 illustrates a pore size distribution curve of anion-exchange layered silicate used in Comparative Example 1.

[0027]FIG. 4 illustrates prepolymerization activity patterns of Example5, Example 9 and Comparative Example 3.

[0028]FIG. 5 illustrates various states of prepolymerization activitypatterns.

EXPLANATION OF MARKS

[0029] D_(VM) represents a maximum peak intensity, Dm represents a poresize diameter showing a maximum peak intensity, and D_(m ½)represents apore size diameter on the smaller diameter side corresponding to apoint, the peak intensity of which is ½ of the maximum peak intensity.

BEST MODE FOR CARRYING OUT THE INVENTION

[0030] Hereinafter, the present invention is described in more details.(Catalyst component for olefin polymerization) (1) Physical propertiesof carrier

[0031] A catalyst component for olefin polymerization of the presentinvention employs an ion-exchange layered silicate having the followingfeatures 1 and 2:

[0032] feature 1: in a pore size distribution curve calculated fromdesorption isotherm by nitrogen adsorption-desorption method, a porediameter Dm showing a maximum peak intensity D_(VM) is from 60 to 200 Å;and

[0033] feature 2: in a pore size distribution curve calculated fromdesorption isotherm by nitrogen adsorption-desorption method, a porediameter D_(m½)(Å) on the smaller pore size side corresponding to a ½peak intensity of the maximum peak intensity D_(VM) has a relation ofD_(m½)D_(m) of at least 0.65 and less than 1 (the largest value isemployed when there are a plurality of D_(m½)values).

[0034] Nitrogen adsorption-desorption method

[0035] Measurement of adsorption-desorption isotherm by nitrogenadsorption-desorption method is explained hereinafter. A nitrogen gas isused for this measurement. When evaluating a pore size distribution, anitrogen gas is used since it has satisfactory properties as a generaladsorption gas.

[0036] The evaluation of the pore size distribution in the presentinvention employs desorption isotherm. The desorption isotherm is acurve obtained while reducing a relative pressure. The desorptionisotherm shows a lower relative pressure to the same desorpted gasamount as compared with adsorption isotherm, and consequently shows alower free energy state, and is generally considered to be closer to astate of real thermodynamical stability.

[0037] Examples of the above analyzing apparatus include commerciallyavailable products such as Autosorb of Quanta Chrome Company, Belsorp,of Nippon Bell Co. or Omnisorp of Coulter Inc. or the like. The presentinvention employs BJH method most general as a calculation method ofpore size distribution.

[0038] An example of a measuring method is illustrated below. Themeasurement is carried out at a temperature of 77K under a relativepressure P/P₀ (P₀=atmospheric pressure) of from 0.02 to 1. In accordancewith the BJH method, pore diameters (unit: Å) are expressed by the axisof abscissas and differential values of pore volumes (unit: cm³/g) areexpressed by the axis of ordinates. It is sufficient that themeasurement time is generally one time.

[0039] Pore size distribution

[0040] D_(m) represents a pore diameter corresponding to the maximumvalue of values of ordinate (differential values of pore volumes), andis generally expressed as “most frequently appearing pore diameter”.FIG. 1 illustrates an example of a graph showing pore size distribution.With regard to the pore size distribution curve of FIG. 1 (Example 1), apore diameter of 101 Å corresponds to the most frequently appearing porediameter, i.e. a pore diameter appearing in the highest proportion amongall pore volumes. The ordinate value of D_(m) is the maximum peakintensity D_(Vm). D_(m½)represents a pore diameter corresponding to apoint on the smaller diameter side showing a half value of the maximumvalue D_(VM) of ordinate. In FIG. 1, a pore diameter of 77 Å correspondsto D_(m½). That is, a D_(m½)/D_(m) ratio is taken as a measure ofdistribution based on the smaller pore side, and this value becomessmaller if the distribution is narrower. In FIG. 1, D_(m ½)/D_(m) is77/101=0.76. Also, depending on shapes of pore size distribution curves,there is a case in which there are a plurality of D_(m½)values, and insuch a case, the largest value is decided to be the D_(m½)value.

[0041] A pore diameter size showing the maximum peak intensity(generally referred to as “most frequently appearing pore diameter”) isin a range of from 60 to 200 Å, preferably from 70 to 190 Å, morepreferably from 80 to 180 Å. If the pore diameter Dm showing the maximumpeak intensity D_(VM) exceeds 200 Å, a carrier strength is lowered, andproperties of polymer particles become unpreferably poor.

[0042] On the other hand, if the Dm value is less than 60 Å, uniformactivation of a catalyst and uniform growth of polymer particles arehardly achieved and agglomeration of polymer particles or deposition ofpolymer particles on a reactor are caused.

[0043] A pore diameter D_(m½)is present at least one respectively onboth sides of D_(m), i.e. on the larger diameter side of D_(m) and onthe smaller diameter side of D_(m), but a value on the smaller diameterside is taken as the D_(m½)value in the present invention. Also, ifthere are a plurality of D_(m½)values on the smaller diameter side, thelargest value is employed for calculation. A D_(m½)/D_(m) value ispreferably at least 0.68, more preferably at least 0.70. If theD_(m½)/D_(m) value is less than 0.68, it is not preferable since aconsiderable amount of small size pores are contained.

[0044] By using an ion-exchange layered silicate having the above“feature 1” and “feature 2” for an olefin polymerization catalystcomponent (cocatalyst) as an activating agent for a metallocene complex,the following function mechanism is considered to work. Thus, theion-exchange layered silicate has a predetermined size pore, but itspore size is sufficiently large to a metallocene complex, an organicaluminum compound and a monomer. Accordingly, these compoundsparticipating in the reaction easily enter into pores in respectivestages of formation of a catalyst, activation, prepolymerization andpolymerization, and complexes are highly dispersed in carriers, andconsequently metallocene catalyst active sites are uniformly formed.

[0045] Further, it is very important for uniform growth of catalystparticles to have carriers dispersed in a form of fine particles alongwith growth of polymer particles, and carriers having such a specificpore size distribution as defined in the present invention areconsidered to achieve this effect. In the polymerization reaction, sucha catalyst inhibits local heat generation on the catalyst as comparedwith a conventional catalyst. Particularly when producing an easilymeltable or soluble polymer, it is possible to carry out a highly activepolymerization in a state of maintaining satisfactory particles, e.g. ina propylene type low melting point random polymerization, which couldnot be conventionally achieved.

[0046] Carrier strength

[0047] In the present invention, it is preferable to maintain a carrierstrength of an ion-exchange layered silicate within a predeterminedrange. Thus, it is preferable to satisfy the following “feature 3”.

[0048] Feature 3: an average crushing strength of an ion-exchangelayered silicate measured by a minute compression tester is at least 3MPa.

[0049] If the carrier strength is too low, catalyst powder and polymerparticles are easily crushed to produce fine powders which degradeflowing properties and adhesive properties and lower a bulk density.Accordingly, in the present invention, it is important that an averagecrushing strength of a carrier should be at least 3 MPa. Preferably, theaverage crushing strength is at least 5 MPa, more preferably at least 7MPa.

[0050] On the other hand, if the carrier strength is too high, particlegrowth during prepolymerization or polymerization becomes ununiform andthere is a fear of producing fine powders. Accordingly, the upper limitof the carrier strength is preferably an average crushing strength of atmost 20 MPa, more preferably at most 18 MPa. Even when prepolymerizationis carried out, the upper limit and the lower limit of an averagecrushing strength are adjusted in the same manner as above, and areeffectively in a range of from 3 to 18 MPa.

[0051] The ion-exchange layered silicate of the present inventionpreferably has the feature 3 in addition to the above feature 1 andfeature 2, but further has the following features (feature 4 isdescribed hereinafter).

[0052] Feature 5: in a pore size distribution curve calculated fromdesorption isotherm by nitrogen adsorption-desorption method, a porediameter D_(m⅓)on the smaller pore size side corresponding to a ⅓ peakintensity of the maximum peak intensity D_(VM) has a relation ofD_(m⅓)/D_(m) of at least 0.55 and less than 1 (provided that if thereare a plurality of D_(m⅓)values, the largest value is employed forD_(⅓)).

[0053] Such a pore diameter D_(⅓)value is present respectively on bothsides of D_(m), i.e. at least one on the larger diameter side of D_(m)and at least one on the smaller diameter side of D_(m), but in thepresent invention, a value on the smaller diameter side is defined asD_(m⅓). Also, when there are a plurality of D_(m⅓)values on the smallerdiameter side, the largest value is employed for calculation. AD_(m⅓)/D_(m) value is preferably at least 0.56, more preferably at least0.57. If the D_(m⅓)/D_(m) value is less than 0.56, a considerable amountof smaller diameter pores are contained, such being unpreferable.

[0054] Feature 6: a pore size distribution calculated from desorptionisotherm by nitrogen adsorption-desorption method has substantiallyunimodal peak.

[0055] That is, there is not present a second peak, and if it ispresent, its intensity is at most 50%, preferably at most 40%,particularly at most 30% of a maximum peak intensity D_(VM).

[0056] Feature 7: BET surface area is from 150 to 250 m²/g.

[0057] The surface area controls a site capable of being an active site,and has a possibility of preventing fusion, and an ion-exchange layeredsilicate having a BET surface area value within this range ispreferable.

[0058] Feature 8: a pore volume is from 0.2 to 2.0 cm³/g, preferablyfrom 0.25 to 1.8 cm³/g, more preferably from 0.3 to 1.5 cm³/g.

[0059] Feature 9: in a pore size distribution curve calculated fromdesorption isotherm by nitrogen adsorption-desorption method, wherein apeak intensity at a pore diameter of 50 Å is defined as D_(V50) _(Å) ,D_(V50) _(Å) /D_(VM) is at least 0.01 and at most 0.40, preferably atleast 0.03 and at most 0.38, more preferably at least 0.05 and at most0.36.

[0060] If the D_(V50) _(Å) /D_(VM) value exceeds 0.38, a considerableamount of smaller diameter pores are contained, such being unpreferable.

[0061] (2) Ion-exchange layered silicate

[0062] In the present invention, an ion-exchange layered silicate usedas a starting material is a silicate compound having a crystal structurewherein planes formed by ionic bond are laminated in parallel withmutual bonding force and ions contained between planes are exchangeable.Most of ion-exchange layered silicates naturally occur as a maincomponent of clay minerals, and often contain impurities (such asquartz, cristobalite or the like), but it is all right to contain theseimpurities. Also, the starting material of the present invention means asilicate at a stage before chemical treatment of the present inventionas described below. Further, the ion-exchange layered silicates used inthe present invention may be not only naturally occurring materials butalso artificially synthesized materials.

[0063] Examples of these ion-exchange layered silicates may be thefollowing materials as described in “Clay Minerals (Nendo Kobutsu Gaku)”written by Haruo Shiramizu (published by Asakura Shoten in 1995).

[0064] (a) Examples of an ion-exchange layered silicate comprising a 1:1layer as a main constituting layer include kaolin group silicates suchas dickite, nacrite, kaolinite, anauxite, metahalloysite, halloysite orthe like, and serpentine group silicates such as chrysotile, lizaldite,antigorite or the like.

[0065] (b) Examples of an ion-exchange layered silicate comprising a 2:1layer as a main constituting layer include smectite group silicates suchas montmorillonite, zauconite, beidellite, nontronite, saponite,hectorite, stephensite or the like, vermiculite group silicates such asvermiculite or the like, mica group silicates such as mica, illite,sericite, glauconite or the like, and attapulgite, sepiolite,palygorskite, bentonite, pyrophyllite, talc, chlorites and the like.

[0066] A silicate used as a starting material in the present inventionmay be a layer-like silicate having a mixture layer of the above (a) and(b) groups formed. In the present invention, it is preferable to use asilicate having the 2:1 type layer as the main component, preferably thesmectite group, particularly montmorillonite. A kind of intercalationcations is not specially limited, but a silicate having an alkali metalor alkali earth metal as a main component for an intercalation cation ispreferable in respect that such a silicate is relatively easilyavailable at a low cost as an industrial starting material.

[0067] Chemical treatment

[0068] An ion-exchange layered silicate used in the present inventionmay be a naturally occurring material or a material available for anindustrial starting material as it is, but it is preferable forobtaining a highly active catalyst to have the ion-exchange layeredsilicate subjected to a chemical treatment. Examples of the chemicaltreatment include an acid treatment, an alkali treatment, a salttreatment, an organic material treatment and the like. The chemicaltreatment employed may be any of a surface treatment for removingimpurities deposited on a surface and a treatment having an influence ona structure of clay. It is possible to employ the chemical treatment inorder to obtain such properties of pore size distribution as defined inthe present invention.

[0069] The acid treatment removes impurities on a surface but also canelute a part or all of cations such as Al, Fe, Mg or the like in acrystal structure. An acid used in the acid treatment is selectedpreferably from hydrochloric acid, sulfuric acid, nitric acid,phosphoric acid, acetic acid and oxalic acid. Usually, the acid is usedin a form of an acid aqueous solution. The acid used in the treatmentmay be a mixture of at least two kinds of acids.

[0070] General treating conditions with acid may be optionally selectedfrom an acid concentration in a range of from 0.1 to 50 wt%, a treatingtemperature in a range of from room temperature to a boiling point and atreating time in a range of from 5 minutes to 24 hours. It is preferableto carry out the treatment under such conditions as to elute at least apart of a material constituting at least one kind of compound selectedfrom the group of ion-exchange layered silicates.

[0071] A particularly preferable embodiment of the present invention isto carry out a treatment with an acid having a specific concentration.That is, it is preferable to carry out a treatment with an acid havingan acid concentration (N) satisfying the following formula at leastonce. In the present invention, this operation is referred to as“concentrated acid treatment”.

N≧-6.0

[0072] The acid concentration N is defined as (mol number ofacid)×(valence number of acid)/(volume of acid aqueous solution) (unit:mol/L) . However, a salt coexists, a crystal water amount contained in asalt compound is considered, but a volume change by the salt is notconsidered. A specific gravity of the acid aqueous solution was sitedfrom Basic Edition II-4 of Chemical Handbook (Kagaku Binran) (by theJapan Chemical Society, published by Maruzen, revised third edition).

[0073] It is not clear why the treatment of an ion-exchange layeredsilicate under such specific conditions is effective, but it isconsidered as described below.

[0074] Generally, it is known that by subjecting the silicate to acidtreatment, impurities on its surface are removed and cations such as Al,Fe, Mg or the like in its crystal structure are eluted, therebyincreasing a surface area. Thus, in accordance with the progress of acidtreatment, it is considered that a surface area and a pore volume areincreased. However, in case of such concentrated acid treatment ascarried out in the present invention, a surface area value of a silicatetreated by the concentrated acid treatment employing such an acidconcentration (N) as defined in the present invention is rather smallerthan a surface area of a silicate treated by an acid treatment employinga lower acid concentration to have the same constituting componentseluted. This fact means that a pore size of the silicate becomes larger.It is expected that this change achieves an effect of easily moving amaterial between an outer part and an inner part of a catalyst. Thus, asilicate treated by an acid having a high concentration provides alarger pore size, and it is expected that material movement (of ametallocene complex, a monomer, an organic aluminum compound or thelike) becomes easy in the inside of a catalyst or constituting particlesin the same manner as in the outside. Accordingly, a catalyst preparedfrom the silicate of the present invention has active sites moreuniformly dispersed, and it is considered that a local heat generationon the catalyst is inhibited as compared with a conventional catalyst.Particularly, when producing an easily meltable or soluble polymer, e.g.in a case of low melting point random polymerization of a propylene typemonomer, it is possible to carry out polymerization at a high activityand in a state of maintaining dispersed particles, which could not beconventionally achieved.

[0075] A more preferable range of the acid concentration range of theacid concentration (N) (mol number of acid)×(valence number ofacid)/(volume of acid aqueous solution) (unit: liter) of the presentinvention is at least 6.0, preferably at least 7.0. The upper limit ofthe acid concentration N is preferably at most 20, particularly at most15, in view of handling safety, easiness and equipments.

[0076] An acid used for the concentrated acid treatment may be the sameas those used in an ordinary acid treatment, but is preferably sulfuricacid, nitric acid or hydrochloric acid, more preferably sulfuric acid.By such a specific treatment, an ion-exchange layered silicate havingthe above-mentioned feature 1 and feature 2 and/or at least oneproperties selected from feature 3 and feature 5 to feature 9 can beobtained. Further, in the present invention, it is preferable to carryout a salt treatment. The salt treatment means a treatment carried outfor the purpose of exchanging cations in an ion-exchange layeredsilicate. The treating conditions with a salt are not specially limited,but it is preferable to carry out the salt treatment under conditions ofa salt concentration of from 0.1 to 50 wt%, a treating temperature offrom room temperature to a boiling point and a treating time of from 5minutes to 24 hours in such a manner as to elute at least a part ofmaterials constituting an ion-exchange layered silicate. Also, the saltmay be used in an organic solvent such as toluene, n-heptane, ethanol orthe like, or may be used in the absence of a solvent if it isliquid-like at the treating temperature, but it is preferably used as anaqueous solution. However, depending on a kind of a salt employed, thesalt treatment achieves an effect similar to an acid treatment.

[0077] In the present invention, it is preferable to ion exchange atleast 40%, preferably at least 60% of ion-exchangeable cations of Group1 metals contained in an ion-exchange layered silicate with cationsdissociated from the following salts.

[0078] Usable salts include a compound obtained from a cation containingat least one atom selected from the group consisting of Group 1 to 14atoms and at least one anion selected from the group consisting of ahalogen atom, an inorganic acid and an organic acid, preferably acompound obtained from a cation containing at least one atom selectedfrom the group consisting of Groups 2 to 14 atoms and at least one anionselected from the group consisting of Cl, Br, I, F, PO₄, SO₄, NO_(3,)CO_(3,) C₂O₄, OCOCH₃, CH₃COCHCOCH₃, OCl₃, O(NO₃)₂, O(ClO₄)₂, O(SO₄), OH,O₂Cl₂, OCl₃, OCOH, OCOCH₂CH₃, C₂H₄O₄ and C₆H₅O₇.

[0079] Examples of the salts include Li₂SO4, CaCl₂, CaSO₄, CaC₂O₄,Ca(NO₃)₂, Ca₃(C₆H₅O₇)₂, MgCl_(2,) Sc(OCOCH₃)₂, ScF₃, ScBr₃,Y(OCOCH₃)_(3,) LaPO₄, La₂(SO₄)_(3,) Sm(OCOCH₃)₃, SmCl₃, Yb(NO₃)₃,Yb(ClO₄)₃, Ti(OCOCH₃)₄, Ti(CO₃)₂, Ti(SO₄)₂, TiF₄, TiCl_(4,) Zr(OCOCH₃)₄,Zr(CO₃)₂, Zr(NO₃)₄, ZrOCl₂, Hf(SO₄)₂, HfI₄, HfBr₄, V(CH₃COCHCOCH₃)₃,VOSO₄, VCl₄, VBr₄, Nb(CH₃COCHCOCH₃)_(5,) Nb₂(CO₃)₅, Ta₂(CO₃)_(5,)Ta(NO)5, TaCl₅, Cr(OOCH₃)₂OH, Cr(NO₃)₃, Cr(ClO₄)₃, MoOCl₄, MoCl₃, MoCl₄,MOCl_(5,) MoF₆, WCl₄, WBr₅, Mn(CH₃COCHCOCH₃)₂, Mn(NO₃)₂, Fe(OCOCH₃)_(2,)Fe(NO₃)₃, FeSO₄, Co(OCOCH₃)_(2,) Co₃(PO₄)_(2,) CoBr₂, NiCO₃, NiC₂O₄,Pb(OCOCH₃)₄, Pb(OOCH₃)₂, PbCO_(3,) Pb(NO₃)_(2,) CuI₂, CuBr₂, CuC₂O₄,Zn(OOCH₃)₂, Zn(CH₃COCHCOCH₃)_(2,) ZnSO₄, Cd(OCOCH₂CH₃)₂, CdF₂, AlCl₃,Al₂ (C₂O₄)_(3,) Al(CH₃COCHCOCH₃)_(3,) GeCl_(4,) GeBr₄, Sn(OCOCH₃)₄,Sn(SO₄)₂, and the like.

[0080] At least two kinds of salts and acids may be used. When combininga salt treatment and an acid treatment, there are a method of carryingout an acid treatment after conducting a salt treatment, a method ofcarrying out a salt treatment after conducting an acid treatment, and amethod of carrying out a salt treatment and an acid treatment at thesame time.

[0081] Examples of a chemical treatment with other compounds include analkali treatment with LiOH, NaOH, KOH, Mg(OH)₂, Ca(OH)₂, Sr(OH)₂,Ba(OH)₂ or the like, and an organic material treatment with trimethylammonium, triethyl ammonium or the like. Examples of an anionconstituting an organic material treating agent includehexafluorophosphate, tetrafluoroborate, tetraphenylborate or the like,in addition to anions illustrated as an anion constituting a salttreating agent, but should not be limited thereto.

[0082] Granulation

[0083] An average particle size of a silicate of the present inventionis preferably at least 5 μm and at most 100 μm. If there are presentmany fine particles having an average particle size of less than 5 μm,polymers are agglomerated and easily adhered to a reactor, and anunpreferable short pass or a long term retention is caused depending ona polymerization process. On the other hand, coarse particles having anaverage particle size of at least 100 μm are liable to cause occlusion(for example, at the time of catalyst feeding), such being unpreferable.If particles do not cause such problems, they may be a naturallyoccurring material or a commercially available material, which may beused as it is, and also these materials may be used after adjustingtheir particle sizes by classification operation, separation operationor the like.

[0084] A granulation method is not specially limited as far as it is amethod for providing particles satisfying the above-mentioned particlesize and shape conditions, but a spray granulation method is preferable.As mentioned above, a particle strength can be controlled duringgranulation step. In order to obtain a crushing strength in a preferablerange, it is preferable to regranulate pulverized silicate particles ofthe present invention. The silicate may be pulverized by any method. Asa pulverization method, any method of dry system pulverization or wetsystem pulverization may be used, but wet system pulverization ispreferable. Wet system pulverization means a pulverization methodemploying swelling properties of a silicate by using water as adispersion medium. Examples of the method include a method of employingcompulsory stirring system with polytron or the like, and a method ofemploying dynomill, pearl mill or the like. Before granulation, particlesize and a volume fraction of particles of less than 1 μm are an averageparticle size of from 0.01 to 5 μm and a particle fraction of less than1 μm of at least 10%, preferably an average particle size of from 0.1 to3 μm and a particle fraction of less than 1 μm of at least 40%. Adispersing agent used for spray granulation is usually water.

[0085] Granulated particles preferably have a sphere-like shape. Aconcentration of a silicate in a starting material slurry for spraygranulation to obtain sphere-like particles depends on a slurryviscosity but is generally from 0.1 to 50%, preferably from 1 to 30%,more preferably from 2 to 20%. A temperature at a hot air entrance forspray granulation to obtain sphere-like particles varies depending on adispersion medium, but in a case of water, it is from 80 to 260° C.,preferably from 100 to 220° C.

[0086] In order to produce a silicate having a specific pore sizedistribution of the present invention, it is preferable to carry outgranulation before a chemical treatment.

[0087] Generally, an ion-exchange layered silicate contains adsorbedwater and intercalation water. In the present invention, it ispreferable to remove adsorbed water and intercalation water previouslybefore using the silicate. It is usual to employ a heat treatment forremoving water. Its method is not specially limited, but it is necessaryto select such conditions as not to remain adsorbed water andintercalation water and not to destroy its structure. The heating timeis at least 0.5 hour, preferably at least one hour. In such a case, awater content after the removal is at most 3 wt%, preferably at most 1wt%, as compared with a water content of 0 wt% defined when the silicateis dehydrated at a temperature of 200° C. under a pressure of 1 mmHg for2 hours.

[0088] Treatment with organic aluminum compound

[0089] In the present invention, in order to prevent a catalytic activesite from being poisoned with water remained or a hydroxyl group presentin an ion-exchange layered silicate, the ion-exchange layered silicatemay be subjected to contact treatment with an organic aluminum compound(in the present specification, such an organic aluminum compound as usedfor treating the silicate is referred to as “organic AL(1)”) beforeprepolymerization or main polymerization. As the organic AL(1), anorganic aluminum compound having an optional structure is generallyusable. The ion-exchange layered silicate mentioned herein is preferablya silicate treated as mentioned above (including a combination of aplurality of treatments).

[0090] Particularly, by using the silicate treated with an organicaluminum compound having a specific structure, not only its activity isimproved but also it is possible to reduce agglomeration of polymerparticles and a polymer amount fused onto a polymerization tank wall ora pipe wall in polymerization atmosphere. The organic aluminum compoundhaving a specific structure is expressed by the following formula (X).

AlR_(n)Y_(3−n)   (X)

[0091] (R is a hydrocarbon group having a carbon number of from 4 to 12,Y is hydrogen, halogen, an alkoxy group or a siloxy group, and n is anumber larger than 0 and at most 3.)

[0092] Examples of a preferable organic aluminum compound includetri-n-butylaluminum, triisobutylaluminum, tri-n-pentylauminum,tri-n-hexylaluminum, tri-n-heptylaluminium, tri-n-octylaluminum,tri-n-decylaluminum, tri-n-dodecylaluminum, diisobutylaluminum chloride,di-n-octylaluminum chloride, diisobutylaluminum hydride,di-n-octylaluminum hydride, diisobutylaluminum ethoxide,di-n-octylaluminum ethoxide, and the like.

[0093] Also, it is possible to use a combination of organic aluminumcompounds wherein n is different. For example, it is possible to use amixture of organic aluminum compounds expressed by the followingformula.

(Oct)_(2. 5)(Et)_(0.5)AL

[0094] wherein Oct=C₈H₁₇ and Et=C₂H₅.

[0095] Among these compounds, preferable examples include a trialkylaluminum (n=3) and a dialkyl aluminum hydride. More preferable examplesinclude a C₄-C₁₂ trialkyl aluminum, concrete examples of which includetriisobutyl aluminum and tri-n-octyl aluminum.

[0096] It is not clear why the above effect can be achieved, but whentreating a carrier with an organic aluminum compound such as tri-n-octylaluminum (TnOA) having a longer alkyl chain and a more bulky substituentas compared with conventionally used triethyl aluminum, it is consideredthat a cohering force of primary particles constituting a carrier islowered and a carrier strength is weakened, and accordingly a uniformgrowth becomes possible. Consequently, it is expected that apolymerization heat and a heat removal per unit volume are considerablywell balanced, and agglomeration by fusion between polymers anddeposition of a melted polymer on a polymerization tank wall can beprevented. Also, by relaxing agglomeration of particles and improving abulk density of a polymer, productivity can be improved.

[0097] Contact between an ion-exchange layered silicate and an organicAL (1) can be carried out under an inert gas atmosphere such as nitrogenin a solvent of an inert hydrocarbon such as hexane, heptane, pentane,cyclohexane, benzene, toluene, xylene or the like, and the solvent maybe used alone or in a mixture of two or more.

[0098] An amount of an organic AL (1) used is preferably from 0.01 to1,000 mmol, more preferably from 0.1 to 100 mmol, per 1 g of anion-exchange layered silicate.

[0099] A concentration of an ion-exchange layered silicate in a solventis preferably from 0.001 to 100 g/mL, more preferably from 0.01 to 10g/mL, and a concentration of an organic AL (1) is preferably from 0.001to 100 mmol/mL, more preferably from 0.01 to 10 mmol.

[0100] Contacting may be carried out by dispersing an ion-exchangelayered silicate in a solvent and then bringing an organic AL (1) incontact therewith. Alternatively, contacting may be carried out byadding an organic AL (1) to a solvent and then dispersing anion-exchange layered silicate therein.

[0101] The contacting treatment is carried out generally at atemperature of from −50° C. to a boiling point of a solvent, preferablyfrom 0° C. to a boiling point of a solvent. The contacting time is from1 minute to 48 hours, preferably from 1 minute to 24 hours.

[0102] The order of contacting an organic AL (1) with an ion-exchangelayered silicate is not specially limited as far as the object of thepresent invention is achieved, but it is more effective to carry out thecontacting treatment after chemical treatment of the silicate orpreferably after drying carried out after the chemical treatment.

[0103] Also, the order of the contacting treatment step of an organic AL(1) and an ion-exchange layered silicate and the granulation step of anion-exchange layered silicate is not specially limited as far as theobject of the present invention is achieved, but it is preferable tocarry out the treatment with an organic AL (1) after granulating thesilicate.

[0104] Further, it is possible to enhance the effect of the presentinvention by combining the above-mentioned respective treatments. Thus,after controlling a particle size distribution and a carrier particlestrength by granulating an ion-exchange layered silicate, a carrierobtained through the following Step 1 and Step 2 is used as a catalystcomponent for olefin polymerization.

[0105] Step 1: after granulating an ion-exchange layered silicate, thesilicate is treated with an acid having an acid concentration (N)satisfying the following formula (I),

N≧6.0   (Formula (I))

[0106] wherein the acid concentration N is expressed by (mol number ofacid)×(valency number of acid)/(volume of acid aqueous solution)(unit:liter).

[0107] Step 2: after carrying out the step 1, the silicate is treatedwith an organic AL (1) which is an organic aluminum compound having analkyl group having at least 4 carbon number.

[0108] (Olefin polymerization catalyst)

[0109] In the present invention, an olefin polymerization catalyst canbe prepared by contacting component (A) and component (B), andoptionally component (C).

[0110] Component (A): a metallocene compound of Groups 4 to 6 of thePeriodic Table

[0111] Component (B): an ion-exchange layered silicate having theabove-mentioned feature 1 and feature 2

[0112] Component (C): an organic aluminum compound

[0113] As the component (B), such various embodiments as described inthe above paragraph “catalyst component for olefin polymerization” canbe used.

[0114] <Explanation of component (A)>

[0115] A metallocene compound used in the present invention is atransition metal compound of Groups 4 to 6 of the Periodic Table, whichhas at least one conjugated 5-membered ring ligand. Preferable examplesof such a transition metal compound include compounds expressed by thefollowing formulae (1), (2), (3) and (4).

[0116] Wherein A and A′ are conjugated 5-membered ring ligands which mayhave a substituent (A and A′ may be same or different in the samecompound), Q is a bonding group crosslinking two conjugated 5-memberedring ligands at an optional position, Z is a ligand containing anitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom or asulfer atom, Q′ is a bonding group crosslinking Z with a conjugated5-membered ring ligand at an optional position, M is a metal atomselected from the group consisting of Groups 4 to 6 of the PeriodicTable, and X and Y are a hydrogen atom, a halogen atom, a hydrocarbongroup, an alkoxy group, an amino group, a phosphorus-containinghydrocarbon group or a silicon-containing hydrocarbon group (X and Y maybe the same or different in the same compound).

[0117] Examples of A and A′ include a cyclopentadienyl group. Thecyclopentadienyl group may contain 5 hydrogen atoms (C₅H₅-), or itsderivative, and some of the hydrogen atoms may be substituted with asubstituent.

[0118] Examples of the substituent include a C₁-C₄₀, preferably C₁-C₃₀hydrocarbon group. This hydrocarbon group may be bonded as a monovalentgroup to a cyclopentadienyl group, or if there are present a pluralityof groups, two of them may be respectively bonded to other terminals(ω-terminal) to form a ring together with a part of cyclopentadienyl.Later examples include a condensed 6-membered ring wherein twosubstituents are respectively bonded to ω-terminals together withadjacent two carbon atoms in the cyclopentadienyl group such as anindenyl group, a tetrahydroindenyl group or a fluorenyl group, and acondensed 7-membered ring such as an azulenyl group or atetrahydroazulenyl group.

[0119] Thus, examples of conjugated 5-membered ring ligands representedby A and A′ include a cyclopentadienyl group, an indenyl group, afluorenyl group or an azulenyl group, which may be substituted orunsubstituted. Among them, a preferable example is an azulenyl group.

[0120] Examples of a substituent on the cyclopentadienyl group includethe above-mentioned C₁-C₄₀, preferably C₁-C₃₀ hydrocarbon group, as wellas a halogen atom group such as fluorine, chlorine or bromine, a C₁-C₁₂alkoxy group, a silicon-containing hydrocarbon group expressed by -Si(R¹) (R²) (R³), a phosphorus-containing hydrocarbon group expressed by-P(R¹) (R²), or a boron-containing hydrocarbon group expressed by -B(R¹)(R²). If there are present a plurality of these substituents, thesesubstituents may be the same or different. The above-mentioned R¹, R²and R³ may be the same or different, and are alkyl groups having acarbon number of from 1 to 24, preferably from 1 to 18.

[0121] Q is a bonding group crosslinking two conjugated 5-membered ringligands at an optional position, and Q′ is a bonding group crosslinkinga group represented by Z with a conjugated 5-membered ring ligand at anoptional position.

[0122] Examples of Q and Q′ include,

[0123] (a) alkylene groups such as a methylene group, an ethylene group,an isopropylene group, a phenylmethylmethylene group, adiphenylmethylene group or a cyclohexylene group,

[0124] (b) silylene groups such as a dimethylsilylene group, adiethylsilylene group, a dipropylsilylene group, a diphenylsilylenegroup, a methylethylsilylene group, a methylphenylsilylene group, amethyl-t-butylsilylene group, a disilylene group or atetramethyldisilylene group, and

[0125] (c) hydrocarbon groups containing germanium, phosphorus,nitrogen, boron or aluminum, concrete examples of which include(CH₃)₂Ge, (C₆H₅)₂Ge, (CH₃)P, (C₆H₅)P, (C₄H₉)N, (C₆H₅)N, (C₄H₉)B,(C₆H₅)B, (C₆H₅)Al and (C₆H₅O)Al. Preferable examples include alkylenegroups and silylene groups.

[0126] M is a transition metal atom selected from the group consistingof Groups 4 to 6 of the Periodic Table, preferably Group 4 metal atomsof the Periodic Table, concrete examples of which include titanium,zirconium, hafnium and the like. Particularly, zirconium and hafnium arepreferable.

[0127] Z is a ligand including a nitrogen atom, an oxygen atom, asilicon atom, a phosphorus atom or a sulfur atom, or a hydrogen atom, ahalogen atom or a hydrocarbon group. Preferable examples include anoxygen atom, a sulfur atom, a C₁-C₂₀, preferably C₁-Cl₂ thioalkoxygroup, a C₁-C₄₀, preferably C₁-C₁₈ silicon-containing hydrocarbon group,a C₁-C₄₀,preferably C₁-C₁₈ nitrogen-containing hydrocarbon group, aC₁-C₄₀, preferably C₁-C₁₈ phosphorus- containing hydrocarbon group, ahydrogen atom, chlorine, bromine, or a C₁-C₂₀ hydrocarbon group.

[0128] X and Y are respectively hydrogen, a halogen atom, a C₁-C₂₀,preferably C₁-C₁₀ hydrocarbon group, a C₁-C₂₀, preferably C₁-C₁₀ alkoxygroup, an amino group, a C₁-C₂₀, preferably C₁-C₁₂ phosphorus-containinghydrocarbon group such as a diphenylphosphino group, or a C₁-C₂₀,preferably C₁-C₁₂ silicon-containing hydrocarbon group such as atrimethylsilyl group or a bis(trimethylsilyl)methyl group. X and Y maybe the same or different. Among them, a halogen atom, a hydrocarbongroup, particularly a C₁-C₈ hydrocarbon group, and an amino group arepreferable.

[0129] (a) Examples of a compound expressed by the formula (1) includebis(methylcyclopentadienyl)zirconium dichloride,bis(ethylcyclopentadienyl)zirconium dichloride,bis(propylcyclopentadienyl)zirconium dichloride,bis(n-butylcyclopentadienyl)zirconium dichloride,bis(1,3-dimethylcyclopentadienyl)zirconium dichloride,bis(1-ethyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1-n-butyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1-i-butyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1-t-butyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1,3-dimethylcyclopentadienyl)zirconium dimethyl,bis(1,3-dimethylcyclopentadienyl)zirconium methylchloride,bis(1,3-dimethylcyclopentadienyl)zirconium diethyl,bis(1,3-dimethylcyclopentadienyl)zirconium diisobutyl,bis(1,3-dimethylcyclopentadienyl)zirconium chloride monohydride,bis(1-n-butyl-3-methyl-cyclopentadienyl)zirconium dihydride,bis(1,3-dimethylcyclopentadienyl)zirconium dimethoxide,bis(1,3-dimethylcyclopentadienyl)zirconium bis(dimethylamide),bis(1-n-butyl-3-methyl-cyclopentadienyl)zirconiumdiethylamidomonochloride,bis(1-methyl-3-trifluoromethylcyclopentadienyl)zirconium dichloride,bis(1-methyl-3-trimethylsilylcyclopentadienyl)zirconium dichloride,bis(1-cyclohexyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1-methyl-3-phenylcyclopentadienyl)zirconium dichloride,bis(1-benzyl-3-methylcyclopentadienyl)zirconium dichloride,bis(1-n-butyl-3-trifluoromethylcyclopentadienyl)zirconium dichloride,bis(indenyl)zirconium dichloride, bis(tetrahydroindenyl)zirconiumdichloride, bis(2-methyl-tetrahydroindenyl)zirconium dichloride, and thelike.

[0130] (b) Examples of a compound expressed by the formula (2) includedimethylsilylenebis{l-(2-methyl-4-isopropyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis{1-(2-methyl-4-phenyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(4-fluorophenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(4-chlorophenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(3-chlorophenyl)-4H-azulenyl)]zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(2,6-dimethylphenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis{1-(2-methyl-4,6-diisopropyl-4H-azulenyl)}zirconiumdichloride,diphenylsilylenebis{1-(2-methyl-4-phenyl-4H-azulenyl)}zirconiumdichloride,methylphenylsilylenebis{1-(2-methyl-4-phenyl-4H-4azulenyl)}zirconiumdichloride,dimethylphenylsilylenebis[1-{2-methyl-4-(1-naphthyl)-4H-azulenyl}]zirconiumdichloride,methylphenylsilylenebis[1-{2-methyl-4-(4-chlorophenyl)-4H-azulenyl}]zirconiumdichloride,methylphenylsilylenebis[1-{2-methy1-4-(4-fluorophenyl)-4H-azulenyl}]zirconiumdichloride,methylphenylsilylenebis[1-{2-methyl-4-(3-chlorophenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis{1-(2-ethyl-4-phenyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(1-naphthyl)-4H-azulenyl)]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconiumdichloride,dimethylsilylenebis[1-(2-ethyl-4-(4-fluorophenyl)-4H-azulenyl)]zirconiumdichloride, dimethylsilylenebis[1-{2-ethyl-4-(3-chlorophenyl)-4H-azulenyl)]zirconium dichloride,dimethylsilylenebis[1-{2-ethyl-4-(2-naphthyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(1-anthracenyl)-4H-azulenyl)]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(2-anthracenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(9-anthracenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(1-phenanthryl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(9-phenanthryl)-4H-azulenyl}]zirconiumdichloride,dimethylmethylenebis{1-[2-methyl-4-(4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylgelmylenebis{1-[2-methyl-4-(4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,ethylenebis{1-[2-methyl-4-(4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-i-propyl-4-(4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-methyl-4-(2-fluoro-4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis-[1-[2-ethyl-4-(2-fluoro-4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-methyl-4-(2′,6′-dimethyl-4-biphenylyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-methyl-4-(1-naphthyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-i-propyl-4-(1-naphthyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-i-propyl-4-(4-t-butylphenyl)-4H-azulenyl]}zirconiumdichloride,dimethylsilylene1-[2-methyl-4-(4-biphenylyl)-4H-azulenyl]}{1-[2-methyl-4-(4-biphenylyl)indenyl]}zirconiumdichloride,dimethylsilylenebis{1-[2-ethyl-4-(4-biphenylyl)-4H-5,6,7,8-tetrahydroazulenyl]}zirconiumdichloride,dimethylsilylene{1-(2-ethyl-4-phenyl-4H-azulenyl)}{1-(2-methyl-4,5-benzoindenyl))zirconiumdichloride,dimethylsilylenebis{1-(2-ethyl-4-phenyl-6-isopropyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis1-(2-ethyl-4,6-diphenyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(pentafluorophenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis{l-(2-ethyl-4-phenyl-7-fluoro-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis{1-(2-ethyl-4-indolyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis{1-(2-dimethylborano-4-indolyl-4H-azulenyl)}zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(3,5-bistrifluoromethylphenyl)-4H-azulenyl}]zirconiumdichloride,dimethylsilylenebis{1-(2-methyl-4-phenyl-4H-azulenyl)}zirconiumdimethyl,dimethylsilylenebis{1-(2-methyl-4-phenyl-4H-azulenyl)}zirconiumbis(trifluoromethanesulfonic acid), dimethylsilylenebis{1-(2-methyl-4-phenylindenyl)}zirconium dichloride,dimethylsilylenebis{1-(2-methyl-4,5-benzoindenyl)}zirconium dichloride,dimethylsilylenebis[1-{2-methyl-4-(1-naphthyl)indenyl}]zirconiumdichloride,dimethylsilylenebis{1-(2-methyl-4,6-diisopropylindenyl))zirconiumdichloride, diphenylsilylenebis{1-(2-methyl-4-phenylindenyl)}zirconiumdichloride,methylphenylsilylenebis{1-(2-methyl-4-phenylindenyl))zirconiumdichloride, dimethylsilylenebis{1-(2-ethyl-4-phenylindenyl)}zirconiumdichloride,dimethylsilylenebis[l-{2-ethyl-4-(1-naphthyl)indenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(9-anthryl)indenyl}]zirconiumdichloride,dimethylsilylenebis[1-{2-ethyl-4-(9-phenanthryl)indenyl}]zirconiumdichloride,dimethylsilylene{1-(2-ethyl-4-phenylindenyl)}{1-(2-methyl-4,5-benzoindenyl)}zirconiumdichloride,dimethylsilylenebis[1-{2-methyl-4-(pentafluorophenyl)indenyl}]zirconiumdichloride,dimethylsilylenebis{1-(2-ethyl-4-phenyl-7-fluoroindenyl)}zirconiumdichloride, ethylene-1,2-bis{1-(2-methyl-4-phenylindenyl)}zirconiumdichloride, ethylene-1,2-bis{1-(2-ethyl-4-phenylindenyl)}zirconiumdichloride,ethylene-1,2-bis[1-{2-methyl-4-(1-naphthyl)indenyl}]zirconiumdichloride, isopropylidenebis{1-(2-methyl-4-phenylindenyl)}zirconiumdichloride, ethylene-1,2-bis[1-{2-methyl-4-phenyl-4H-azulenyl)}zirconiumdichloride, ethylene-1,2-bis{1-(2-ethyl-4-phenyl-4H-azulenyl))zirconiumdichloride,ethylene-1,2-bis[1-(2-methyl-4-(1-naphthyl)indenyl}]zirconiumdichloride,ethylene-1,2-bis[1-{2-methyl-4-(4-chlorophenyl)-4H-azulenyl}]zirconiumdichloride,isopropylidenebis{1-(2-methyl-4-phenyl-4H-azulenyl)}zirconiumdichloride, ethylene-1,2-bis{1-(2-ethyl-4-indolyl-4H-azulenyl)}zirconiumdichloride, dimethylgelmylenebis{1-(2-methyl-4-phenylindenyl)}zirconiumdichloride, dimethylgelmylenebis{1-(2-ethyl-4-phenylindenyl)}zirconiumdichloride, methyl aluminum bis{1-(2-ethyl-4-phenylindenyl)}zirconiumdichloride, phenylphosphinobis{l-(2-ethyl-4-phenylindenyl)}zirconiumdichloride, phenylaminobis{l-(2-methyl-4-phenylindenyl)}zirconiumdichloride, and the like.

[0131] (c) Examples of a compound expressed by the formula (3) include(tetramethylcyclopentadienyl)titanium(bis t-butylamide)dichloride,(tetramethylcyclopentadienyl)titanium(bisisopropylamide) dichloride,(tetramethylcyclopentadienyl)titanium(biscyclododecylamid e)dichloride,(tetramethylcyclopentadienyl)titanium{bis(trimethylsilyl)amide}dichloride,(2-methyl-4-phenyl-4H-azulenyl)titanium{bis(trimethylsilyl)amide}dichloride,(2-methyl-4-phenyl-4H-azulenyl)zirconium{bis(trimethylsilyl)amide}dichloride,(2-methylindenyl)titanium(bis t-butylamide)dichloride,(fluorenyl)titanium(bis t-butylamide)dichloride,(3,6-diisopropylfluorenyl)titanium(bis t-butylamide)dichloride,(tetramethylcyclopentadienyl)titanium(phenoxide)dichlorid e,(tetramethylcyclopentadienyl)titanium(2,6-diisopropylphenoxide)dichloride,and the like.

[0132] (d) Examples of a compound expressed by the formula (4) includedimethylsilanediil(tetramethylcyclopentadienyl)(t-butylamide)titaniumdichloride, dimethylsilanediil(tetramethylcyclopentadienyl)(cyclododecylamide)titanium dichloride,dimethylsilanediil(2-methylindenyl)(t-butylamide)titanium dichloride,dimethylsilanediil(fluorenyl)(t-butylamide)titanium dichloride, and thelike.

[0133] Component (A) expressed by the formulae (1) to (4) may be used ina mixture of two or more compounds expressed by the same formula and/ordifferent formula.

[0134] Component (C)

[0135] Component (C) is an organic aluminum compound, and is optionallyused. A compound expressed by the following formula (5) is preferablyused.

AlR⁴ _(p)X_(3-p)   Formula (5)

[0136] wherein R⁴ is a C₁-C₂₀ hydrocarbon group, and X is halogen,hydrogen, an alkoxy group or an amino group, and p is in a range of from1 to 3.

[0137] R⁴ is preferably an alkyl group, and X is preferably chlorine,when it is halogen, a C₁-C₈ alkoxy group when it is an alkoxy group, anda C₁-C₈ amino group when it is an amino group.

[0138] In the present invention, a compound expressed by this formulamay be used alone or in a mixture or in a combination of a plurality ofcompounds. This can be used not only at the time of preparing a catalystbut also at the time of prepolymerization or polymerization.

[0139] Accordingly, preferable compound examples includetrimethylaluminum, triethylaluminum, tri n-propylaluminum, trin-butylaluminum, triisobutylaluminum, tri n-hexylaluminum, trin-octylaluminum, tri n-decylaluminum, diethylaluminum chloride,diethylaluminum sesqui chloride, diethylaluminum hydride,diethylaluminum ethoxide, diethylaluminum dimethylamide,diisobutylaluminum hydride, diisobutylaluminum chloride, and the like.Among them, preferable examples include a trialkylaluminum wherein p=3,a dialkylaluminum hydride wherein p=2 and X=hydrogen, and the like. Morepreferable examples include a trialkylaluminum wherein R⁴ has a carbonnumber of from 1 to 8, and most preferable example istriisobutylaluminum.

[0140] (Preparation of catalyst)

[0141] A catalyst of the present invention can be formed by contactingthe above respective components in the outside of a polymerizationreactor or the inside of the polymerization reactor at the same time orcontinuously or by one time or a plurality of times. It is usual tocarry out the contacting treatment of respective components in a solventof an aliphatic hydrocarbon or an aromatic hydrocarbon. A contactingtemperature is not specially limited, but is preferably from −20° C. to150° C. Depending on an aimed object, an optional combination can beemployed as a contacting order, but a preferable contacting order withregard to the respective components is illustrated below. Usually,component (B) is contacted with component (A) at first. Addition ofcomponent (C) to component (B) may be carried out before contacting withcomponent (A) or at the same time or after contacting with component(A), but it is preferable to add component (C) to component (B) at thesame time as contacting with component (A) or after contacting withcomponent (A). After contacting the respective components, it ispossible to wash with an aliphatic hydrocarbon or aromatic hydrocarbonsolvent.

[0142] Respective amounts of components (A), (B) and (C) used in thepresent invention are optional. For example, an amount of component (A)to component (B) is preferably from 0.1 to 1,000 μmol, more preferablyfrom 0.5 to 500 umol to 1 g of component (B). An amount of component (C)to component (B) is preferably from 0.001 to 100 μmol, preferably from0.005 to 50 μmol, in terms of an amount of a transition metal, to 1 g ofcomponent (B). Accordingly, an amount of component (C) to component (A)is preferably from 0-5 to 50, more preferably from 10⁻⁴ to 5 in terms ofa mol ratio of a transition metal.

[0143] (Prepolymerization catalyst)

[0144] The catalyst of the present invention may be subjected toprepolymerization treatment by contacting the catalyst with apolymerizable monomer to polymerize a small amount of monomer, and it ispreferable to employ the prepolymerization treatment. It is usual toemploy milder conditions for the prepolymerization treatment thanconditions of main polymerization. As a prepolymerization monomer,α-olefin, preferably ethylene or propylene, is usable. A prepolymerizedpolymer amount is usually from 0.01 to 100 g/g-catalyst, preferably from0.1 to 50 g/g-catalyst, more preferably from 1 to 30 g/g- catalyst, mostpreferably from 1.5 to 5 g/g-catalyst. If this amount is too small,powder properties of a polymer obtained become poor, and if this amountis too large, it is not preferable from economical viewpoint.

[0145] The prepolymerization catalyst is obtained by combining theabove-mentioned components (A) and (B), and an organic aluminum compound(hereinafter, an organic aluminum compound used for prepolymerization isreferred to as “organic AL (2)”) used optionally if desired. Thecomponent (A) is a metallocene compound and the component (B) is anion-exchange layered silicate. The ion-exchange layered silicate of thecomponent (B) may be such various embodiments as fully described in theparagraph “catalyst component for olefin polymerization”. However, it ispreferable to use a catalyst having a specific structure obtained bycombining the above-mentioned specific treatments. A specific structuremeans to have “feature 1” and “feature 2”, and preferably to have, inaddition to these features, at least one property selected from “feature3” and “feature 5 to feature 9”. The organic AL (2) is not speciallylimited, but the same material as the above-mentioned component (C) issuitable.

[0146] Preferable embodiments of the prepolymerization catalyst toachieve the effect of the present invention are illustrated as thefollowing embodiments (1) to (5). (1) It is important thatprepolymerization catalyst particles obtained by contacting ametallocene catalyst supported on an ion-exchange layered silicate witholefin have the following “feature 4”.

[0147] Feature 4: A prepolymerization homogenization index (H value)obtained by subjecting respective catalyst particles beforeprepolymerization and after prepolymerization to fluorescenceobservation is at most 60%.

[0148] An ion-exchange layered silicate mentioned herein is notspecially limited, and such various silicates as fully described withregard to “catalyst component for olefin polymerization” as component(B) are usable.

[0149] The present inventors have carried out morphological analysis ofa prepolymerization catalyst to study relation between polymerproperties and outer appearance of a product, and as this result, it hasbeen discovered that (a) a agglomerated material of polymer particlesobtained by polymerization and (b) catalyst particles causing a poorouter appearance of a product such as fish eyes and gel have clearcharacteristics. It has been discovered that the problems of the presentinvention can be solved by reducing such particles, and the presentinvention has been accomplished on the basis of this discovery.

[0150] It is a well known technique to prepolymerize a metallocenecatalyst, but its solving means was simply to change a kind of eachcatalyst component or prepolymerization conditions. As far as thepresent inventors know, there was no example of solving theabove-mentioned problems of a prepolymerization catalyst from amorphological viewpoint. In the present invention, the prepolymerizationcatalyst has been studied from its morphological viewpoint.

[0151] Fluorescence analysis is employed as a means for analyzing themorphology. Particles before prepolymerization emit a fluorescent light,but its fluorescent light density varies after the prepolymerization.The fluorescent light density means a fluorescent light intensityemitted when applying UV rays to a catalyst. An H value which is amorphological index is expressed by percentage indicating a proportionof a number of “fluorescent light-emitting particles” present amongprepolymerization catalyst particles. The “fluorescent light-emittingparticles” are defined as catalyst particles having a fluorescent lightdensity of at least 1 after prepolymerization when an averagefluorescent light density of catalyst particles before prepolymerizationis defined to be 1.

[0152] Catalyst particles causing agglomeration of polymerization powderare (a) particles having a low prepolymerization degree per piece ofparticle or (b) particles having a part of low prepolymerization degreeremained within particle.

[0153] These particles are clearly characterized by subjecting acatalyst to fluorescence observation. Their characteristics and amechanism of exhibiting the characteristics are estimated as mentionedbelow.

[0154] (a) Particles having a low prepolymerization degree per piece ofparticle

[0155] When carrying out fluorescence observation, these particles arecharacterized by having a fluorescent light density not lower than afluorescent light density of catalyst particles beforeprepolymerization. A mechanism that the catalyst emits a fluorescentlight is not clear, but it is estimated that the fluorescent light isemitted from a component of an organic metal compound which becomes anactive site when considering an inorganic carrier before contacting withthe organic metal compound (such as a metallocene compound) whichbecomes an active site does not substantially emit a fluorescent lightand a catalyst after contacting with the organic metal compound emits afluorescent light.

[0156] A fluorescent light density varies depending on aprepolymerization degree of particles, and the fluorescent light densitybecomes larger at a stage of low prepolymerization degree than that of acatalyst before prepolymerization. The stage of low prepolymerizationdegree is a stage in which a volume of a prepolymerization polymer issmaller than a pore volume of an inorganic carrier, and at this stage,the prepolymerization polymer is accumulated within pores of theinorganic carrier and this is a stage in which the inorganic carrier isnot crushed nor dispersed.

[0157] At such a stage that the prepolymerization polymer is beingfilled in these pores, fluorescence observation shows that the catalystprovides a fluorescent light density higher than that beforeprepolymerization.

[0158] When the prepolymerization proceeds further, a volume of theprepolymerization polymer becomes larger than the pore volume of theinorganic carrier, and in proportion to growth of the polymer, theinorganic carrier is crushed and dispersed. At this proceeded stage, thecomponent (organic metal compound) emitting a fluorescent light is goingto be dispersed in the prepolymerization polymer in accordance withdispersion of the inorganic carrier, and a density of the component(organic metal compound) emitting a fluorescent light present per unitvolume becomes smaller as the prepolymerization degree becomes larger.Consequently, a fluorescent light density becomes smaller.

[0159] However, not all of catalyst particles grow until this stage, andgrowth of a part of particles are suspended at a stage of lowprepolymerization degree depending on prepolymerization conditions.These particles provide a poor outer appearance of a product due to poorparticle properties, fish eyes or gel. The present invention solves theabove-mentioned problems by providing a prepolymerization catalysthaving a uniform prepolymerization degree among particles.

[0160] (b) Particles having a part of low prepolymerization degreeremained at a part within particle

[0161] Depending on prepolymerization conditions, particles having apart of low prepolymerization degree remained at a part within catalystparticle are formed. This is because when rapid prepolymerization iscarried out, diffusion of a monomer is not sufficiently developed in theinside of a particle, and prepolymerization proceeds only on thesurface. According to fluorescence observation of these particles, afluorescent light density of the part of low prepolymerization degreebecomes higher than that of a catalyst before prepolymerization, andother part provides a low fluorescent light density. The reason why thepart of low prepolymerization degree provides a higher fluorescent lightdensity is the same as described in the above paragraph (a), and it isconsidered that this is because a density of a component (organic metalcompound) providing a fluorescent light present per unit volume is high.Powders having these characteristics also cause a bad outer appearanceof a product due to poor powder properties, fish eyes and gel.

[0162] As described in the above paragraph (b), the present inventionsolves the above problems by providing a catalyst having whole particleof each particle uniformly fully polymerized.

[0163] Comparison of fluorescent light density of catalyst particleafter prepolymerization

[0164] The present invention is characterized in that there are presentonly a small number of catalyst particles (fluorescent light-emittingparticles) after prepolymerization, the fluorescent light density ofwhich is at least 1 to a fluorescent light density of catalyst particlesbefore prepolymerization. That is, a proportion (H value) of a number ofcatalyst particles after prepolymerization, the fluorescent lightdensity of which is at least 1 to a fluorescent light density ofcatalyst particles before prepolymerization, is at most 60% to a numberof whole catalyst particles after prepolymerization.

[0165] Thus, it is preferable that a number of fluorescentlight-emitting particles is smaller, and an H value is preferably atmost 50%, more preferably at most 40%, most preferably at most 30%.

[0166] The fluorescent light density is an intensity of fluorescentlight emitted when UV rays are applied to a catalyst, and is evaluatedby a brightness of fluorescence microscope photograph. On the basis of afluorescent photograph of a catalyst before prepolymerization taken bythe following method, largeness and smallness of a fluorescent lightdensity are evaluated by comparing a brightness between this photographand a photograph of a catalyst after prepolymerization. As thebrightness is higher, the fluorescent light density becomes large.Comparison of the brightness can be visually made, but it can be made byusing an image-analyzing apparatus using a computer.

[0167] Observation conditions by microscope

[0168] Both fluorescent light observation and transmitting lightobservation are carried out by bathing a sample in liquid paraffin. Anordinary catalyst is deactivated when contacting with air, but themeasurement can be made even when the sample is deactivated.

[0169] It is necessary to select photographing conditions of afluorescent light photograph in such a manner as to be able to evaluatelargeness and smallness of a fluorescent light density of catalystparticles after prepolymerization as compared with a fluorescent lightdensity of particles before prepolymerization. In order to makeevaluation easier, it is possible to select conditions so as not to bephotosensitive when a fluorescent light density is smaller than that ofa catalyst before prepolymerization.

[0170] Fluorescent light density of catalyst particles beforeprepolymerization

[0171] First, a transparent light photograph of a catalyst beforeprepolymerization is taken and a number of particles is calculatedwithin its visual field and then a fluorescent light photograph is takenin the same visual field.

[0172] With regard to a catalyst before prepolymerization, any particleand any part within a particle have substantially the same fluorescentlight density per area, but when an intensity varies depending on aparticle of catalyst particles before prepolymerization, their averagevalue is employed. It is preferable to use an image-treating apparatusfor calculating an average value.

[0173] It is preferable that there are at least 50 pieces of particlesin the same visual field, but if it is difficult to taken such aphotograph depending on a particle size or dispersibility of a catalyst,a plurality of photographs are taken under the same conditions, and atleast 50 pieces of particles are evaluated.

[0174] A catalyst before prepolymerization for measuring a fluorescentlight density may be employed by taking a part thereof in the process ofobtaining a catalyst after prepolymerization, or a catalyst may beseparately prepared under the same conditions as in the preparation of acatalyst after prepolymerization but without carrying out aprepolymerization step.

[0175] Fluorescent light density of catalyst particles afterprepolymerization

[0176] In the same manner as above, a transmitting light photograph of acatalyst after prepolymerization is taken first, and a number ofparticles within the visual field are calculated and an area of eachparticle on the photograph is determined from the transmitting lightphotograph. Further, a fluorescent light photograph is taken under thesame conditions as in the case of the catalyst before prepolymerizationto look for fluorescent light-emitting particles.

[0177] Depending on particles after prepolymerization, there is a casethat only a part of each particle emits a fluorescent light. In such acase, as an evaluation standard as to whether that is a fluorescentlight- emitting particle or not, a particle having an effectivefluorescent light-emitting part area of at least {fraction (1/100)} toan area of the particle on the transmitting light photograph is judgedto be a fluorescent light-emitting particle. In this manner, with regardto 50 pieces of particles, their fluorescent light density is comparedwith that of a catalyst before prepolymerization. Crushed catalyst orfine powder-like catalyst particles are not preferable as a catalyst forpolymerization, and if such particles are added to be measured, a numberof particles to be measured is increased and consequently an H valuebecomes a lower value, thus apparently exhibiting a favorablemeasurement result. In order to remove this influence, catalystparticles having a particle size of at most ¼ of an average catalystparticle size are not calculated.

[0178] Fluorescence microscope

[0179] A fluorescence microscope employed is a fluorescence microscopeas described at page 421 of “Rikougaku Jiten” edited by Tokyo RikaDaigaku Rikougaku Jiten Henshuu Iinkai or at pages 70 to 74 of“Kenbikyou no Ohanashi” by Kentarou Asakura. Examples of a fluorescencemicroscope include a transmission fluorescence microscope and areflection fluorescence microscope, and the reflection fluorescencemicroscope is employed for observation in the present specification.Also, it is preferable for preventing a sample from being damaged tomake the time of applying a fluorescent light to a sample shorter, andthe measurement is finished preferably within at most 5 minutes, morepreferably within at most 1 minute.

[0180] A catalyst component and prepolymerization conditions to be usedare not specially limited as far as a prepolymerization catalyst havingthe above-mentioned feature 4 can be obtained.

[0181] (a) A prepolymerization catalyst having feature 4 can be obtainedby using a silicate having a specific structure formed by combining suchspecific treatments as described in the above paragraph “Catalystcomponent for olefin polymerization”. The specific structure means tohave feature 1 and feature 2, preferably further to have at least oneproperty selected from the group consisting of feature 3 and feature 5to feature 9, in addition thereto.

[0182] (b) Also, a prepolymerization catalyst having feature 4 can beobtained by employing at least one of the following procedures (2) to(5).

[0183] Further, it is effective to combine the above methods (a) and(b).

[0184] (2) It is important to employ specific prepolymerizationconditions.

[0185] According to prior arts, there was no disclosure concerning aknowledge to associate with a polymerization performance of a catalystobtained in relation to a feeding method of a monomer inprepolymerization. It has been discovered in the present invention thata feeding method of olefin in prepolymerization system provides animportant influence on a catalyst performance, and the above-mentionedproblems of the present invention have been solved on the basis of thisdiscovery.

[0186] That is, the present invention relates to a catalyst for olefinpolymerization, which is a prepolymerization catalyst obtained bycontacting a metallocene catalyst supported on an ion-exchange layeredsilicate with olefin, wherein the catalyst is obtained by (b)maintaining a polymer-forming rate at most 10 mg/min per g of theion-exchange layered silicate (a) until a prepolymerized polymer in anamount of corresponding to a pore volume of the ion-exchange layeredsilicate is formed.

[0187] The above metallocene catalyst supported is obtained by combiningthe above-mentioned components (A) and (B). The component (A) is ametallocene compound and the component (B) is an ion-exchange layeredsilicate. Various types of materials as fully described in the aboveparagraph “catalyst component for olefin polymerization” can be used asthe ion-exchange layered silicate of the component (B). However, it ispreferable to use a carrier having a specific structure obtained bycombining the above-mentioned specific treatments. The specificstructure has “feature 1” and “feature 2”, and in addition to theseproperties, preferably has at least one property selected from “feature3” and “feature 5 to feature 9”.

[0188] Generally, olefin polymerization of a catalyst supported on acarrier takes a step wherein catalyst particles collapse in accordancewith growth of polymer particles. If a growth speed of polymer particlesand a collapse speed of carriers are not well balanced, collapse ofparticles and generation of fine powder are caused. From this point ofview, it is necessary to carry out prepolymerization in a good balancewith a carrier strength in order to prevent growth of non- uniformparticles. Particularly, since an ion-exchange layered silicate has acleavage property, a balance between a growth speed of polymer particlesand a collapse speed of carriers has a large influence on catalystperformances. The present inventors considered this point veryimportant.

[0189] The polymer growth speed in prepolymerization can be adjusted bycontrolling reaction conditions including an olefin concentration, acomponent (A) concentration, an organic AL (2) concentration, a slurryconcentration of a catalyst component, a prepolymerization temperature,a prepolymerization pressure and the like. For example, it is convenientfor this purpose to control a rate of supplying olefin to polymerizationsystem, an olefin partial pressure and the like.

[0190] Olefin may be any form of liquid or gas in the prepolymerizationsystem. Olefin may be introduced previously in a specific-amount into areactor before prepolymerization, or may be supplied step by step orcontinuously, but it is preferable to supply olefin step by step orcontinuously. Particularly, when supplying olefin step by step orcontinuously, a feeding rate per hour of olefin is usually from 0.001 to100 g, preferably from 0.01 to 10 g, per g of component (B). Moreparticularly, the feeding of olefin may be suspended intermittentlyduring prepolymerization, or the feeding rate may be varied as a lapseof time. Also, it is possible to use hydrogen together with olefin foradjusting a molecular weight if necessary. Also, it is possible tocontrol the reaction by using an inert gas such as nitrogen, lowering apressure by purging during the reaction, diluting with an inert solventor varying a prepolymerization temperature to adjust a polymer-formingrate.

[0191] When carrying out prepolymerization in accordance with a slurrypolymerization method in an inert solvent, a component (A) concentrationis usually from 0.001 to 100 μmol/mL, preferably from 0.01 to 10μmol/mL. In the same manner, a component (B) concentration is usuallyfrom 0.001 to 100 g/mL, preferably from 0.005 to 10 g/mL. Also, anorganic AL (2) concentration is usually from 0.01 to 1,000 μmol/mL,preferably from 0.1 to 100 /μmol/mL.

[0192] Prepolymerization by contacting the above catalyst component witholefin is carried out at a temperature in a range of usually from −50°C. to 100° C., preferably from 0° C. to 90° C. Particularly, when anolefin concentration is high, the temperature employed is preferablylower to control the reaction. The temperature may be constant, but maybe varied as a lapse of time. Particularly, in the initial stage ofprepolymerization, it is preferable not to make a polymerization speedhigher, and thus, it is preferable that the prepolymerization isinitiated at a relatively low temperature and the temperature is thenraised.

[0193] Also, it is possible to control a polymer-forming rate byselecting a kind of olefin. In the present invention, particularly inthe initial stage of prepolymerization, the above-describedprepolymerization conditions are appropriately selected to maintain apolymer-forming rate at a proper value, and this control can be moreeasily made by combining at least two of a plurality of conditions.

[0194] It is necessary for the prepolymerization of the presentinvention to maintain a polymer-forming rate at most 10 mg/min per g ofcomponent (B) until a prepolymerized polymer is formed in an amountcorresponding to a pore volume of the component (B). After forming aprepolymerized polymer in an amount corresponding to the pore volume ofthe component (B), a polymer-forming rate is not specially limited. Theprepolymerization of the present invention is characterized by beingprecisely controlled at the initial stage. For example, in case ofbatch-wise operation, it is necessary to precisely control at theinitial stage for 100 minutes, particularly for 50 minutes, from theinitiation of polymerization. Also, in case of continuous operation, itis necessary to precisely control at the initial zone for 100 minutes,particularly for 50 minutes, of the retention time.

[0195] As mentioned above, the pore volume of the component (B) isvaried depending on a kind of an ion-exchange layered silicate or atreating method employed, but it is usually from 0.2 to 2.0 cm³/g.Accordingly, by taking an amount of component (B) used and its porevolume into consideration, a polymer-forming rate and an amount to beformed in the prepolymerization are controlled.

[0196] Prepolymerization activity pattern

[0197] A polymer-forming rate may be at most 10 mg/min as apolymer-forming rate per g of component (B). If the forming rate exceeds10 mg/g-min, a prepolymerized polymer is non-uniformly formed, and apolymerization active site of a catalyst is hardly increased. A large 10amount of polymer is locally formed, which causes agglomeration of thecatalyst component. According to the present inventors' knowledge, inorder to increase a polymerization active site of a catalyst, it isrequired that an ion-exchange layered silicate is gradually crushed by aformed polymer and its surface area is increased in the step ofprepolymerization. The lower limit of a polymerization rate is notspecially limited, but if it is too low, a long time is necessary forprepolymerization treatment, and it is not industrially favorable.Accordingly, the polymerization rate is selected preferably in a rangeof from 1 to 10 mg/g-min, particularly from 2 to 8 mg/g-min.

[0198] A polymer-forming rate is not always necessary to be constant asfar as it is at most 10 mg/g-min until a prepolymerized polymer isformed in an amount corresponding to a pore volume of component (B). Ifit is at most 10 mg/g-min, any combination of a constant rate, anincreasing rate or a decreasing rate may be employed. As mentionedabove, after forming a prepolymerized polymer in an amount correspondingto a pore volume of component (B), a polymer-forming rate is notspecially limited. When carrying out prepolymerization in batch-wisemanner, a remaining olefin monomer may be purged or all remainingmonomers may be polymerized in a short time by raising a temperature.

[0199] Hereinafter, a forming rate of prepolymerization polymer(prepolymerization activity pattern) is explained with reference tovarious embodiments illustrated in the drawings.

[0200]FIG. 5 illustrates prepolymerization activity patterns (simplyreferred to as “prepolymerization pattern”) by batch-wise method. Theaxis of abscissas indicates a polymerization time (minute) and the axisof ordinates indicates a forming rate of a prepolymerized polymer(g-polymer/g-B component-min). Also, (PI) indicates an initial stagepolymerization peak and (Ps) indicates a latter stage polymerizationpeak.

[0201]FIG. 5 illustrates patterns (1) to (4), and pattern (1)illustrates a pattern wherein after supplying a small amount of amonomer to a prepolymerization system, the supplying of a monomer issuspended half way. A considerable amount of a polymer is formed in theinitial stage of prepolymerization, and the formation of a polymer isthen decreased and thereafter a polymer is formed at almost constantlevel. In the latter stage of prepolymerization, collapse of catalystcomponent (B) proceeds and an active site is rapidly increased, and apolymer-forming rate reaches a peak. Thereafter, a remaining monomerdisappears, and an amount of a polymer formed reaches 0.

[0202] Pattern (2) illustrates a pattern wherein after supplying a smallamount of a monomer to a prepolymerization system, the supplying of amonomer is suspended half way once. After a lapse of a predeterminedtime, a large amount of a monomer is supplied, and further after a lapseof a predetermined time, a remaining monomer is compulsorily purged tofinish the prepolymerization. Since a large amount of a monomer ispresent at the latter stage of prepolymerization, a polymer-forming ratereaches maximum at the end of polymerization.

[0203] Pattern (3) illustrates a pattern wherein after supplying a smallamount of a monomer to a prepolymerization system, the supplying of amonomer is reduced half way in such a manner as to make apolymer-forming rate constant. Since a polymerization activity of acatalyst is increased in the latter stage of prepolymerization, anamount of a monomer supplied is reduced in the latter stage ofprepolymerization as compared with the former stage. When a monomer issupplied in a constant amount, a prepolymerization temperature islowered or a catalyst concentration is lowered so as to preventexcessive polymerization of the supplied monomer. Also, since aprepolymerization activity correlates to a monomer partial pressure ortemperature, there is a case in which a supplied amount of a monomer anda pressure are in an equilibrium relation depending on conditions, andsuch a case provides this pattern without intentionally reducing asupplied amount of monomer.

[0204] Pattern (4) illustrates a model pattern wherein after supplying asmall amount of a monomer to a prepolymerization system, conditions ofthe prepolymerization are changed half way and operation is made in sucha manner as to maintain a polymer-forming rate in the vicinity of themaximum value of the initial stage.

[0205] In any case of patterns (1) to (3), a polymer-forming ratereaches a peak (PI) in the initial stage of prepolymerization, and isthen once lowered. The polymer-forming rate at this peak (P_(I)) ismaintained at most 10 mg/g-min per g of component (B). Thepolymer-forming rate is rapidly increased in the latter stage ofprepolymerization, and reaches a peak (P_(S)) in some cases. Thepolymer-forming rate at this peak may exceed 10 mg/g-min per g ofcomponent (B). In the case of pattern (4), a polymer-forming rate ismaintained constantly in the vicinity of maximum in the total range ofprepolymerization.

[0206] The prepolymerization catalyst thus obtained may be used as it isin main polymerization, or may be used after washing with an inerthydrocarbon solvent. Further, the catalyst thus obtained may be driedbefore using.

[0207] (3) It is important to optimize an amount of an organic AL (2)used at the time of prepolymerization.

[0208] It has been discovered in the present invention that a highcatalytic activity can be achieved without degrading powder propertiesof a polymer obtained by reducing an amount of an organic aluminumcompound used substantially to 0 or only a small amount at the stage ofprepolymerization, which was conventionally required in a large amount,and the present invention has been accomplished on the basis of thisdiscovery.

[0209] An organic AL (2) used at the time of prepolymerization may bethe same as component (C). An amount of an organic AL (2) used is from 0to 10 mol, more preferably at most 8.5 mol, to 1 mol of component (A).The above-mentioned amount of an organic AL (2) indicates the wholeamount of an organic aluminum compound present at the time ofprepolymerization, and includes an amount of an organic AL (1) remainingin the solution, which is used for the above-mentioned treatment ofsilicate.

[0210] Also, an ion-exchange layered silicate mentioned herein is notspecially limited, and various types of silicates may be used, which arefully described as component (B) in the above paragraph “catalystcomponent for olefin polymerization”. However, it is preferable to use acarrier having a specific structure obtained by combining theabove-mentioned specific treatments. The specific structure is to havefeature 1 and feature 2, and preferably in addition to these features,at least one feature selected from feature 3 and feature 5 to feature 9.

[0211] An amount of component (B) and a ratio to component (A) andcomponent (C) are optional, but an amount of component (A) is generallyfrom 0.1 to 1,000 μmol, preferably from 0.5 to 500 μmol, more preferablyfrom 1 to 100 μmol, to 1 g of component (B) . Accordingly, an amount ofcomponent (C) is from 0 to 10 mmol, preferably from 0 to 4.2 mmol, morepreferably from 0 to 0.90 mmol, to 1 g of component (B).

[0212] It is desirable to improve a catalytic activity, but apolymerization heat per unit time naturally becomes large. Accordingly,unless heat is effectively removed in the vicinity of a polymerizationcatalyst, a temperature is locally raised at a microsite, andconsequently there is a fear that polymer particles agglomerate eachother by dissolution or melting of a polymer. However, the efficiency ofthe heat removal can be controlled by using a catalyst component and/ora catalyst having the above-mentioned specific properties or a catalystused for prepolymerization under the above-mentioned specificconditions.

[0213] Also, by combining the above-mentioned methods, the effect of thepresent invention can be remarkably improved. Thus, when carrying outthe prepolymerization, it is preferable to employ specific conditions(a) and (b) and to adjust an amount of an organic aluminum used at thetime of prepolymerization in the above-mentioned range.

[0214] That is, (b) a polymer forming rate is maintained at most 10mg/g-min per 1 g of an ion-exchange layered silicate (a) until aprepolymerization polymer is formed in an amount corresponding to a porevolume of the ion-exchange layered silicate.

[0215] After finishing the prepolymerization, the catalyst may be usedas it is depending on its used form, but it is possible to dry thecatalyst if necessary. When drying the catalyst, in order to prevent thecatalyst from being poisoned with impurities, it is preferable to add anorganic aluminum compound having the same structure as component (C).

[0216] During contacting the above-mentioned respective components orafter contacting, or after finishing the prepolymerization or afterdrying the prepolymerization catalyst, a solid material including apolymer such as polyethylene, polypropylene or the like, and aninorganic oxide such as silica, titanium or the like, may be coexistedor may be contacted therewith. Also, it is possible to employ a methodof contacting component (C) after contacting all the catalyst componentsof the present invention or after carrying out the prepolymerization.

[0217] (4) When forming a prepolymerization catalyst, it is important tohave a new additional metallocene complex contacted with a metallocenecatalyst on a carrier.

[0218] As mentioned above, in the present invention, component (A) andcomponent (C) optionally used, together with a metallocene catalystsupported on component (B), are contacted with olefin to form aprepolymerization catalyst. As mentioned above, in the prepolymerizationstep, by accumulation of a prepolymerized polymer, collapse anddispersion of component (B) proceeds and a surface area is increased. Inproportion to the procedure of prepolymerization, a polymerizationactive site is formed on the dispersed component (B) by contacting withcomponent (A), and an active site precursor structure is newly formed.

[0219] In the present invention, formation of a new active site on theactive site precursor structure is accelerated by contacting (a) a newmetallocene complex and (b) a new organic aluminum compound optionallyused with the metallocene catalyst effecting prepolymerization, and auniform prepolymerization catalyst in which component (B) is highlydispersed, can be provided by reducing particles having a lowprepolymerization degree (growth is suspended) or removing a part of lowprepolymerization degree within a particle, thus accomplishing thepresent invention.

[0220] A new metallocene complex added during the prepolymerization stepto be contacted with the metallocene catalyst effectingprepolymerization may be the same or different from a component definedas a metallocene complex already supported as component (A), and itsamount used is selected in such a manner as to make the total amount ofcomponent (A) and a new metallocene complex in a range of theabove-mentioned amount of component (A) used to component (B). A molratio of component (A) and a new metallocene complex is optional, butpreferably 1:0.01-1:100, more preferably 1:0.1-1:10.

[0221] Also, a new organic aluminum compound optionally used may be thesame or different from a compound defined as component (C), and itsamount used may be defined also in the same manner.

[0222] Contacting of the metallocene catalyst effectingprepolymerization with (a) a new metallocene complex and (b) a neworganic aluminum compound optionally used, may be carried out at anoptional time during the prepolymerization step carried out bycontacting the metallocene catalyst with olefin under theabove-mentioned prepolymerization conditions. Thus, the contacting maybe carried out in the presence of olefin or in the absence of olefin byonce suspending the prepolymerization. Preferably, the contacting iscarried out after a prepolymerized polymer is formed in an amountsufficiently larger to collapse or disperse component (B). For example,it is necessary to optimize by taking a pore volume, a pore sizedistribution and a carrier strength of component (B) used intoconsideration, but the contacting is carried out usually after forming aprepolymerized polymer in an amount of at least 0.1 g, preferably atleast 0.2 g, more preferably at least 0.5 g, per 1 g of component (B).In order to fully achieve an effect by a new metallocene complex,prepolymerization is carried out until a prepolymerized polymer isfurther formed in an amount of at least 0.5 g, preferably at least 1.0g, more preferably at least 2.0 g, per 1 g of component (B).

[0223] (5) In the formation of a prepolymerization catalyst, it isimportant to subject a metallocene catalyst on a carrier prepared underspecific conditions to slurry-washing with an inert hydrocarbon solventor liquefied α-olefin and then to carry out olefin prepolymerization.

[0224] In the step of preparing a metallocene catalyst on a carrier bycontacting component (A) and component (C) optionally used withcomponent (B), it is necessary to optimize the contacting conditions toform an active site by having the component (A) fully supported on thecomponent (B), and this is desirable for forming a uniformprepolymerization catalyst. For example, it is necessary to take asufficient contacting time for completely effecting the carryingreaction. However, according to extension of the contacting time,degeneration of component (A) as a side reaction also proceeds, andconsequently non-uniform prepolymerization is caused. Further, component(A) adsorbed in a carrier during prepolymerization without beingsupported on component (B) causes formation of a deposited polymerduring main polymerization.

[0225] Thus, the present invention is accomplished by providing auniform prepolymerization catalyst having component (B) highlydispersed, which is obtained by the steps of (a) proceeding the carryingreaction by contacting component (A) with component (B) for at least 30minutes, (b) slurry washing the contacted material obtained by the aboveoperation (a) with an inert hydrocarbon solvent or liquefied α-olefin toremove a byproduct derived from component (A) and (c) carrying outolefin prepolymerization with the washed material obtained by the aboveoperation (b) to remove particles having a low prepolymerization degreeor to remove a part of low prepolymerization degree in a particle.

[0226] The contacting operation of component (A) and component (B) iscarried out under such conditions as described in the above paragraph“preparation of catalyst”, but the contacting time is preferably atleast 30 minutes, more preferably at least one hour. The contactingtemperature is not specially limited, but it is necessary to avoid sucha high contacting temperature as to cause degeneration reaction ofcomponent (A), and it is preferable to employ a contacting temperatureof at most 100° C., preferably at most 80° C., more preferably at most60° C.

[0227] (Use of catalyst/polymerization of olefin)

[0228] As a polymerizable α-olefin, a C₂-C₂₀ olefin is preferable,examples of which include ethylene, propylene, 1-butene, 1-hexene,1-octene and the like. In case of copolymerization, a kind of acomonomer used may be α-olefin selected from the above illustratedα-olefins, which is other than the main component. An amount of acomonomer is selected under such conditions as to produce a polymerhaving desirable physical properties (in respect of a melting point, amolecular weight, a stiffness, or the like), and is more effectivelyselected so as to provide a low melting point polymer.

[0229] Any polymerization system may be employed as far as a catalystcomponent and each monomer are efficiently contacted. For example, aslurry method using an inert solvent, a solution polymerization method,a bulk method employing propylene as a solvent substantially withoutusing an inert solvent, or a gas phase method maintaining each monomerin a gas state substantially without using a liquid solvent may beemployed. Also, they are applied to continuous polymerization orbatch-wise polymerization. In case of slurry polymerization, a saturatedaliphatic hydrocarbon or an aromatic hydrocarbon such as hexane,heptane, pentane, cyclohexane, benzene, toluene or the like may be usedalone or in a mixture as a polymerization solvent. A polymerizationtemperature is from 0 to 200° C., and as a molecular weight-regulatingagent, hydrogen may be assistantly used. An operatable polymerizationpressure is from 0 to 2,000 kg/cm²G.

[0230] Also, a metallocene catalyst of the present invention is usedpreferably for producing a random copolymer, and is particularlysuitable for producing a propylene-ethylene copolymer. Also, it issuitable for producing a low melting point polymer, and is particularlysuitable for producing a propylene-ethylene random copolymer having amelting point of at most 140° C., preferably at most 135° C., morepreferably at most 130° C., most preferably at most 125° C.

[0231] The present invention is further illustrated with reference tothe following Examples, but should not be limited thereto.

[0232] In the following Examples and Comparative Examples, physicalproperties were evaluated in the following manner.

[0233] (1) Composition analysis of ion-exchange layered silicate

[0234] Chemical analysis is carried out in accordance with JIS method toprepare an analytical curve, and determination is carried out withfluorescent X-rays.

[0235] (2) Measurement of pore size

[0236] Measurement conditions of pore size distribution by nitrogenadsorption-desorption method are illustrated.

[0237] Apparatus: Autosorb 3, manufactured by Quanta Chrome Company

[0238] Measurement method: gas adsorption method

[0239] Measurement conditions:

[0240] Pretreatment conditions: 200° C., 2 hours, under vacuum (at most10⁻² torr)

[0241] Sample amount: about 0.2 g

[0242] Kind of gas: nitrogen

[0243] Gas liquefaction temperature: 77 K

[0244] (3) Particle size measurement of ion-exchange layered silicate

[0245] A Laser micronizer (“LMS-24”, manufactured by Seishin Kigyo K.K.) was used. Measurement was carried out by using ethanol as adispersion medium, and a particle size distribution and an averageparticle size (median diameter) were calculated in terms of a refractiveindex of 1.33 and a shape coefficient of 1.0.

[0246] (4) MFR measurement

[0247] A melt index value of a polypropylene type polymer was measuredin accordance with JIS-K-6758, and a melt index value of a polyethylenetype polymer was measured in accordance with JIS-K-6760.

[0248] (5) Polymer BD

[0249] A polymer bulk density was measured in accordance with ASTMD1895-69.

[0250] (6) Agglomerated amount of polymer

[0251] By using a sieve of 1,690 μm, a polymer wt% on the sieve shakenfor 10 minutes was measured.

[0252] (7) Evaluation of bulk density of prepolymerization catalyst

[0253] A bulk density was measured by flowing a solid catalyst componentthrough a stainless-made funnel having an exit aperture diameter of 5 mmφ into a 10 cc container to measure a weight as expressed by weight per1 cc.

[0254] (8) Evaluation of flow properties of prepolymerization catalyst

[0255] Flow properties were measured by placing 14 cc of a solidcatalyst component powder into respective stainless-made funnels havinga conical angle of 30° and various flow aperture diameters of 5 mm φ,6.5 mm φ, 8 mm φ, 12 mm φ, and 20 mm φ. Numerical values indicate aminimum aperture diameter which causes flowing.

[0256] (9) Measurement of average crushing strength

[0257] By using a minute compression tester “MCTM-500”manufactured byShimadzu Corporation, crushing strengths of optionally selected at least10 pieces of particles were measured and their average value wascalculated to be a crushing strength of an inorganic carrier.

[0258] (10) Evaluation of prepolymerization homogenization index

[0259] (Fluorescence microscope)

[0260] A fluorescence microscope OPTIPHOT (manufactured by NikonCorporation) having a Epi-fluorescence attachment EDF2 (100 W mercurylamp) equipped is referred to as a fluorescence microscope. Fluorescenceobservation was carried out by a standard UV exciter (using UV-2Afilter: excited by 330-380 nm UV rays) attached to this fluorescencemicroscope.

[0261] (Preparation of microsection)

[0262] A microsection for observation was prepared by using emulsion oilTYPE DF for fluorescence observation manufactured by Nikon Corporationand inserting a sample between a commercially available slide glass anda cover glass.

[0263] (Microscopic observation)

[0264] The above prepared microsection was observed by ordinarytransmitting light observation to confirm a part wherein particles to beobserved are appropriately present, and its image was recorded inaccordance with the following method. Thereafter, the same visual fieldwas observed by fluorescence observation and its image was recorded inaccordance with the same method.

[0265] (Observed image-photographing apparatus)

[0266] A digital microscope VH-7000 manufactured by KEYENCE Company wasconnected with a trinocular tube cone of the above fluorescencemicroscope by way of “TV Lens C-0.6X”manufactured by Nikon Corporationto record an observed image (magnification: about 150 to 300 times).Conditions of CCD of VH-7000 were gain: 0 dB (fixed), shutter speed:{fraction (1/15)} (fixed) and white balance: 1 PUSH. Also, imagequality-improving functions were offset: −5, gain correction: +10 andgamma correction: +5.

[0267] By using a digital color printer VH-P40 manufactured by KEYENCECompany, photograph outputs were determined by printing conditions ofbrightness: +20 and contrast: +20 on the VH-7000 side. With regard toconditions other than the above-mentioned conditions, the initiallyfixed conditions for VH-7000 and VH-P40 were employed as they are.

[0268] (11) Washing rate

[0269] A washing rate indicates a washing degree of decantation washingof a silicate of the present invention after treated with an organicaluminum compound. A total amount of an organic aluminum compoundcontained in a solution after reaction, were defined to be 1, and to thetotal amount, an amount of an organic aluminum compound remained afterwashing was determined in accordance with the following calculationformula. The calculation was made on the assumption that an organicaluminum compound was not separated from the solid side by the washingoperation or was not adsorbed.

[0270] For example, in case of decantation washing operation, a washingrate is calculated in the following manner.

[0271] W₁=(V₀−d₁)/(V₀+P₁)

[0272] W₂=(V₁−d₂)/(V₁+P₂)

[0273] Wn=(V_(n−1)−d_(n))/V_(n−1)

[0274] Washing rate=W₁×W₂ ··×W_(n)

[0275] (wherein Wn represents n th washing rate, V_(n−1) represents asolution amount after (n−1)th washing, dn represents an extracted amountat the time of n th washing, and P_(n) represents an added solventamount at the time of n th washing. 0 time means the time after organicaluminum compound treatment).

[0276] (12) Melting point (Tm)

[0277] By using DSC6200 manufactured by Seiko Instruments K. K., 5 mg ofa sheet-like sample was packed into an aluminum pan, and a temperaturewas raised from room temperature to 200° C. at a raising speed of 100°C./min, and the temperature was maintained for 5 minutes, and the samplewas then cooled to 40° C. at a cooling speed of 10° C./min to have thesample crystallized, and the sample was then heated again to 200° C. ata raising speed of 10° C./min to measure a maximum peak temperature (0°C.) of melting.

EXAMPLE 1

[0278] (Chemical treatment of ion-exchange layered silicate)

[0279] Into a 3 L glass-made separable flask equipped with a stirringvane, 1,130 mL of distilled water was placed therein, and 750 g ofconcentrated sulfuric acid (96%) was slowly added thereto, and 300 g ofmontmorillonite (Benclay SL, manufactured by Mizusawa IndustrialChemicals, Ltd.; average particle size: 25 μm, particle sizedistribution: 10-60 μm, composition (wt%): Al 18.45, Mg 2.14, Fe 2.34,Si 32.8 and Na 2.62) was dispersed therein, and the resultant mixturewas gradually heated to 90° C. for 1 hour, and the temperature wasmaintained for 5.5 hours, and the mixture was then gradually cooled to50° C. for 1 hour. The slurry thus obtained was filtrated under areduced pressure to obtain a cake. The cake thus obtained was washedwith distilled water until the final washing water had a pH of exceeding3.5, and the washed product was dried overnight at 110° C. under anitrogen atmosphere.

[0280] According to nitrogen adsorption method, the product had a mostfrequently appearing pore diameter (D_(m)) of 101 A, a ratio of porediameter showing ½ of a peak intensity of the most frequently appearingpore diameter (D_(m½)/D_(m)) of 0.76, a ratio of a pore diameter showing⅓ of a peak intensity of the most appearing pore diameter (D_(m⅓)/D_(m))of 0.60, and a maximum intensity of pore diameter 50 Å to the maximumintensity (D_(V50) _(A) /D_(VM)) of 0.26. A second peak intensity wasabout 30%. (Pore size distribution is illustrated in FIG. 1.) A porevolume of particles of less than 1,000 A was 0.42 cm /g, and a surfacearea by BET method was 225 m²/g. This carrier had an average crushingstrength of 13 MPa as measured by a minute compression tester.

[0281] The composition (wt%) of this chemically treated montmorillonitewas Al 4.80, Mg 0.70, Fe 1.20, Si 41.2 and Na of less than detectablelimit (0.2). Eluted rates of respective components were Al 55%, Mg 74%,Fe 59% and Na 93%. Mol ratios of respective components to Si were Al0.121, Mg 0.0196, Fe 0.0146 and Na less than 0.0059.

[0282] (Preparation of catalyst/prepolymerization catalyst)

[0283] The following operations were carried out by using deoxidized anddehydrated solvents and monomers under an inert gas.

[0284] The above chemically treated montmorillonite was dried at 200° C.for 2 hours under a reduced pressure. 20 g of the dried montmorillonitewas introduced into a glass-made reactor having an inner volume of 1 Land a stirring paddle, heptane containing 3% of toluene (hereinafterreferred to as “mixed heptane”) and 84 mL of a heptane solutioncontaining triethyl aminium (0.596 M) were added thereto, and theresultant mixture was stirred at room temperature. After 1 hour, mixturewas washed with mixed heptane (washing rate<1/100) to obtain 200 mL of asilicate slurry.

[0285] Thereafter, 87 mL of mixed heptane was added to 218 mg (0.3 mmol)of (r)-dimethylsilylenebis{l-[2-methyl-4-(4-chlorophenyl)-4H-azulenyl]}zirconiumdichloride, and the mixture was fully stirred, and 4.25 mL of a heptanesolution of triisobutyl aluminum (0.706 M) was added thereto, and theresultant mixture was reacted at room temperature for 1 hour.Thereafter, the above prepared silicate slurry was added thereto, andthe resultant mixture was stirred for 1 hour, and mixed heptane wasadded thereto to adjust to 500 mL.

[0286] The above prepared silicate/metallocene complex slurry wasintroduced into an autoclave having an inner volume of 1.0 L and astirring system, which was fully substituted with nitrogen. When atemperature became stably 40° C., propylene was supplied thereto at arate of 10 g/hour, and the temperature was maintained. After four hours,the supplying of propylene was stopped, and the temperature was raisedto 50° C., and was then maintained for further 2 hours. Aprepolymerization catalyst slurry was collected by a syphon, and about300 mL of a supernatant liquid was removed, and the slurry was dried at45° C. under a reduced pressure. By this operation, a prepolymerizationcatalyst containing 1.9 g of polypropylene per 1 g of catalyst wasobtained.

[0287] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 25%.

[0288] (Propylene-ethylene random polymerization)

[0289] A stirring system autoclave having an inner volume of 3 L wasfully substituted with propylene, and 2.76 mL (2.02 mmol) of atriisobutyl aluminum-n-heptane solution was added therein, and 30 g ofethylene, 100 cc of hydrogen and 1,500 mL of liquid propylene wereintroduced therein, and a temperature was raised to 70° C. and thetemperature was maintained. The previously prepared prepolymerizationcatalyst was made into a slurry with n-heptane, and 10 mg (except for aweight of a prepolymerized polymer) of the slurry was charged therein asa catalyst under a pressure to initiate polymerization. The tanktemperature was maintained at 70° C. After 0.5 hour, 5 mL of ethanol wasadded therein, and a polymer obtained by purging the remaining gas wasdried at 90° C. for 10 hours. As this result, 175 g of a polymer wasobtained. A catalyst activity was 35,600 g-PP/g-catalyst·hour. Thepolymer had a bulk density (BD) of 0.45 (g/cc), an MFR value of 8.5(dg/min) and a melting point of 126.8° C. A agglomerated polymer amountof the powder thus obtained was measured and was 0.8%.

[0290] The results are shown in the following Tables 1 and 2. Table 1shows physical properties of an ion-exchange layered silicate and acatalyst, and Table 2 shows polymerization results.

EXAMPLE 2

[0291] (Chemical treatment of ion-exchange layered silicate)

[0292] In a 10 L separable flask, 96% sulfuric acid (3.0 kg) was addedto 4.5 kg of distilled water, and Benclay SL (average particle size 25μm, 1.2 kg) manufactured by Mizusawa Industrial Chemicals, Ltd. as anion-exchange layered silicate (montmorillonite) was added thereto at 90°C., and the temperature was maintained to react for 5 hours. Afterfinishing the reaction, the reaction mixture was cooled and was washedwith pure water to pH 3. A solid obtained was pre-dried at 130° C. for 2days in a nitrogen stream, and coarse particles of not smaller than 70μm were removed. The solid was further dried at 200° C. in a nitrogenstream to obtain 0.80 kg of chemically treated smectite. The chemicallytreated smectite thus obtained had a composition of Al: 4.0 wt%, Si:38.8 wt%, Mg: 0.60 wt%, Fe: 1.3 wt% and Na<0.2 wt%, and Al/Si=0.107(mol/mol). This carrier had an average crushing strength of 11 MPa asmeasured by a minute compression tester.

[0293] This carrier had a frequently appearing pore diameter (D_(m)) of101 A by nitrogen adsorption method, a ratio of pore diameter showing ½of a peak intensity of the most frequently appearing pore diameter(D_(m½)/D_(m)) of 0.82, a ratio of a pore diameter showing ⅓ of a peakintensity of the most frequently appearing pore diameter (D_(m⅓)/D_(m))of 0.71, and a maximum intensity of pore diameter 50 Å to the maximumintensity (D_(V50) _(Å/D) _(VM)) of 0.26. Also, a second peak intensitywas about 20%. (Pore size distribution is illustrated in FIG. 2.) A porevolume of less than 1,000 A was 0.44 cm³/g, and a surface area by BETmethod was 221 m²/g. This carrier had an average crushing strength of 11MPa as measured by a minute compression tester.

[0294] (Preparation of catalyst/prepolymerization catalyst)

[0295] (Preparation of catalyst)

[0296] Into a metallic reactor having an inner volume of 13 L and havinga stirrer, a mixture of 0.20 kg of the above-mentioned dry silicate and0.74 L of heptane containing 3% toluene (hereinafter referred to as“mixed heptane”) was introduced, and 1.26 L of a heptane solution of trin-octyl aluminum (0.40 M) was added thereto, and an inner temperaturewas maintained at 25° C. After reacting for 1 hour, the reaction mixturewas fully washed with mixed heptane to prepare 2.0 L of a silicateslurry.

[0297] On the other hand, 0.80 L of mixed heptane was added to 2.17 g(3.00 mmol) of(r)-dichloro{1,1′-dimethylsilylenebis[2-methyl-4-(4-chlorophenyl)-4H-azulenyl])zirconium,and 21.1 mL of a heptane solution of triisobutyl aluminum (0.71 M) wasadded thereto, and the resultant mixture was reacted at room temperaturefor 1 hour, and the mixture thus obtained was added to the aboveprepared silicate slurry, and the resultant mixture was stirred for 1hour, and mixed heptane was added thereto to adjust the volume to 5.0 L.

[0298] Thereafter, an inner temperature was raised to 40° C. and wasstabilized, and propylene was supplied thereto at a rate of 67 g/hour,and the temperature was maintained. After 6 hours, the supplying ofpropylene was stopped, and the mixture was maintained for further 1hour.

[0299] After finishing the prepolymerization, the remaining monomer waspurged, and a catalyst obtained was fully washed with mixed heptane.Thereafter, 0.17 L of a heptane solution of triisobutyl aluminum (0.71M/L) was added thereto, and the product was dried at 45° C. under areduced pressure. As this result, a prepolymerization catalystcontaining 2.12 g of polypropylene per 1 g of catalyst was obtained.

[0300] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 12%.

[0301] (Propylene-ethylene random polymerization)

[0302] The same procedure as in Example 1 was repeated, except that theabove obtained prepolymerization catalyst was used. As this result, acatalyst activity was 52,100 g/PP/g-catalyst-hour, and a polymer had abulk density (BD) of 0.475 (g/cc), an MFR value of 8.1 (dg/min) and amelting point of 125.7° C., and a agglomerated polymer amount was 2.5%.

EXAMPLE 3

[0303] (Propylene-ethylene random polymerization)

[0304] The same procedure as in Example 1 was repeated, except that theprepolymerization catalyst obtained in Example 2 was employed and apolymerization temperature of 65° C. and 35 g of ethylene were employed.As this result, a catalyst activity was 48,500 g/PP/g-catalyst-hour, anda polymer had a bulk density (BD) of 0.483 (g/cc), an MFR value of 1.6(dg/min) and a melting point of 121.7° C., and a agglomerated polymeramount was 0.9%.

EXAMPLE 4

[0305] (Chemical treatment of ion-exchange layered silicate)

[0306] In a separable flask, 96% sulfuric acid (750 g) was added to1,130 g of distilled water, and Benclay SL (average particle size 27 um,300 g) manufactured by Mizusawa Industrial Chemicals, Ltd. as anion-exchange layered silicate (montmorillonite) was added thereto, andthe mixture was reacted at 90° C. for 390 minutes. Thereafter, thereaction product was washed with distilled water to pH 3. A solidobtained was pre-dried at 130° C. for 2 days in a nitrogen stream, andcoarse particles of not smaller than 53 μm were removed, and the productwas further dried at 200° C. in a nitrogen stream to obtain 140 g ofchemically treated smectite. The chemically treated smectite thusobtained had a composition of Al: 4.6 wt%, Si: 41.5 wt%, Mg: 0.60 wt%,Fe: 0.9 wt% and Na<0.2 wt%, and Al/Si=0.115 (mol/mol). This carrier hadan average crushing strength of 8 MPa as measured by a minutecompression tester.

[0307] This carrier had a frequently appearing pore diameter (D_(m)) of101 Å measured by nitrogen adsorption method, a ratio of pore diametershowing ½ of a peak intensity of the most frequently appearing porediameter (D_(m½)/D_(m)) of 0.83. A pore volume of particles of less than1,000 Å was 0.43 cm³/g.

[0308] (Preparation of catalyst/prepolymerization catalyst)

[0309] A three-forked flask having a volume of 1 L was substituted withdry nitrogen, and 20 g of the above-obtained chemically treated smectitewas placed therein, and 116 mL of heptane was added thereto to prepare aslurry, and 25 mmol of tri n-octyl aluminum was added thereto, and wasstirred for 1 hour, and the resultant product was washed with heptane(washing rate: 1/100), and heptane was added thereto to adjust the totalvolume to 200 mL.

[0310] On the other hand, in another flask (volume 200 mL),(dimethylsilylenebis(2-methyl-4-(p-chlorophenyl)-4H-azulenyl))zirconiumdichloride (218 mg, 0.3 mmol) was added to heptane containing 3% oftoluene to obtain a slurry, and triisobutyl aluminum (3 mmol: 4.26 mL ofa heptane solution having a concentration of 145 mg/mL) was addedthereto, and the resultant mixture was stirred at room temperature for60 minutes to react the mixture.

[0311] The solution thus obtained was introduced into a 1 L flaskcontaining a slurry of the above-obtained chemically treated smectitereacted with tri n-octyl aluminum, and the resultant mixture was stirredfor 1 hour.

[0312] 213 mL of heptane containing 3% of toluene was added to the flaskcontaining the above-obtained catalyst slurry before prepolymerization,and the resultant slurry was introduced into a 1 L autoclave.

[0313] Into the autoclave, propylene was supplied at a rate of 10 g/hourfor 4 hours, and prepolymerization was carried out by maintaining atemperature at 40° C. Thereafter, the supplying of propylene wasstopped, and an inner temperature was raised to 50° C. for 5 minutes,and remaining polymerization was carried out for further 2 hours. Thecatalyst slurry thus obtained was subjected to decantation to remove asupernatant liquid, and triisobutyl aluminum (12 mmol: 17 mL of aheptane solution having a concentration of 140 mg/mL) as adeactivation-preventing agent was added to the remaining portion, andthe resultant mixture was stirred for 10 minutes. A solid obtained wasdried at 40° C. for 3 hours under a reduced pressure to obtain 68.4 g ofa dry prepolymerization catalyst. A prepolymerization magnification (avalue obtained by dividing a prepolymerized polymer amount by a solidcatalyst amount) was 2.42.

[0314] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 28%.

[0315] (Propylene-ethylene random polymerization)

[0316] The same procedure as in Example 1 was repeated, except that theabove-obtained prepolymerization catalyst was used. As this result, acatalyst activity was 40,500 g-PP/g-catalyst-hour, and a polymer had abulk density (BD) of 0.484 (g/cc), an MFR value of 6.1 (dg/min) and amelting point of 125.9° C., and a agglomerated polymer amount was 1.2%.

EXAMPLE 5

[0317] (Chemical treatment of ion-exchange layered silicate)

[0318] In a separable flask, 96% sulfuric acid (2,500 g) was added to3,750 mL of pure water, and 1,000 g of commercially availablemonmorillite (Benclay SL manufactured by Mizusawa Industrial Chemicals,Ltd.) was added thereto, and was made into a slurry by stirring at 60°C. The slurry thus obtained was gradually heated to 90° C. for 1 hour,and was reacted at 90° C. for 5 hours, and the reacted slurry wasgradually cooled to room temperature for 1.5 hours, and was washed withdistilled water until a washing liquid (filtrate) became pH 3. A solidobtained was pre-dried at 130° C. for 2 days in a nitrogen stream, andwas further dried at 200° C. for 6 hours under a reduced pressure toobtain 707.2 g of chemically treated montmorillonite.

[0319] The chemically treated montmorillonite thus obtained had acomposition of Al: 5.21 wt%, Si: 38.9 wt%, Mg: 0.80 wt%, Fe: 1.60 wt%and Na<0.2 wt%, and Al/Si=0.139 (mol/mol).

[0320] The product had an average particle size of 24.5 μm, and anaverage crushing strength of optionally selected 10 pieces ofsphere-like particles was 7.6 MPa. Also, a pore volume was 0.42 cm³/g.The particles thus obtained had a most frequently appearing porediameter (D_(m)) of 90 A by nitrogen adsorption method and a ratio of apore diameter showing ½ of a peak intensity of the most frequentlyappearing pore diameter (D_(m½)/D_(m)) of 0.76.

[0321] (Preparation of catalyst/prepolymerization catalyst)

[0322] In a glass-made reactor having an inner volume of 500 mL, 20.0 gof the above-obtained chemically treated montmorillonite (total porevolume 8.4 cm³) was weighed and placed therein, and 73.7 mL of heptaneand 84.0 mL (50.0 mmol) of a heptane solution of triethyl aluminum wereadded thereto, and the resultant mixture was stirred at room temperaturefor 1 hour. Thereafter, the resultant product was washed with heptane,and a slurry amount was finally adjusted to 200.0 mL.

[0323] On the other hand, 4.26 mL (3003.58 ,μmol) of a heptane solutionof triisobutyl aluminum was added to 87.2 mL (300.37 μmol) of a heptanesolution of(r)-dimethylsilylenebis{1-[2-methyl-4-(4-chlorophenyl)-4H-azulenyl]}zirconiumdichloride at room temperature and the mixture was stirred for 60minutes.

[0324] This complex solution was added to 20.0 g of the above-obtainedmontmorillonite treated with triethyl aluminum, and the resultantmixture was stirred at room temperature for 60 minutes. Thereafter, theresultant mixed slurry was introduced into a stirring system autoclaveof inner volume of 1 L having 209 mL of heptane placed therein, and theresultant mixture was stirred. A temperature in the autoclave wasstabilized at 40° C, and propylene was charged therein at a rate of238.1 mmol/hr (constant rate of 10 g/hr) for 240 minutes. Thereafter,the temperature was raised to 50° C. at a rate of 1° C./min, and wasmaintained for 2 hours, and the remaining gas was purged to recover aprepolymerization catalyst from the autoclave. The total time taken forthe prepolymerization was 6 hours. The recovered catalyst slurry wasallowed to stand, and a supernatant liquid was withdrawn. 17.02 mL(12.02 mmol) of a heptane solution of triisobutyl aluminum was added tothe solid component remained at room temperature, and the resultantmixture was stirred at room temperature for 10 minutes, and was driedunder a reduced pressure to recover 61.8 g of a solid catalystcomponent. The solid catalyst component thus recovered was analyzed, anda prepolymerized propylene weight was 39.4 g.

[0325] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 29%.

[0326] On the other hand, under the same conditions as in the aboveprepolymerization treatment, prepolymerization was initiated, andprepolymerization reaction was suspended at various points as shown inTable 6 (by adding ethanol to purge unreacted remaining gas), and aweight amount of polypropylene formed at the respective points wasdetermined to calculate a polymerization rate at the respective points.Also, a part of a polypropylene amount formed at the respective pointswas calculated from a propylene amount charged upto the respectivepoints and a pressure and a temperature at the respective points withoutsuspending the reaction. An amount of polypropylene formed wasdetermined from a charged propylene amount, from which a propyleneamount in the gaseous phase and a propylene amount dissolved in heptanewere deducted. The results are shown in Table 6.

[0327] Table 6 shows a polypropylene-forming rate of 4 to 7 mg/min per 1g of chemically treated montmorillonite during from 30 minutes to 1 hourafter the initiation of charging propylene and also shows that a lowlevel polypropylene-forming rate of 1 to 3 mg/g-min was maintained after1 hour. The total pore volume of the montmorillonite used was 8.4 cm³,which corresponds to about 9.3 g of a polypropylene amount. Thus, a timerequired for forming an amount of a prepolymerized polymer (about 9.3 gof polypropylene) corresponding to the total pore volume of themontmorillonite is about 210 minutes. In Table 1, a polymer-forming rate(mg/g-min) is shown by a maximum value in the initial stage ofprepolymerization reaction.

[0328] A prepolymerization pattern is illustrated in FIG. 4.

[0329] (Propylene-ethylene random polymerization)

[0330] The same procedure as in Example 1 was repeated, except that theabove-obtained catalyst was used. As this result, an amount of a polymerobtained was 170.0 g, and a catalyst activity was 34,000g-PP/g-catalyst-hour, and a polymer had a bulk density (BD) of 0.441(g/cc), an MFR value of 10.81 (dg/min), an ethylene content of 3.81 wt%and a melting point of 126.5° C. The results are summarized in Table 1and Table 2.

EXAMPLE 6

[0331] (Propylene-ethylene random polymerization)

[0332] The same procedure as in Example 1 was repeated, except that theprepolymerization catalyst prepared in Example 2 was used and 15 g ofethylene and 34 cc of hydrogen were used. As this result, a catalystactivity was 22,000 g-PP/g-catalyst-hour, and a polymer had a bulkdensity (BD) of 0.483 (g/cc), an MFR value of 6.8 (dg/min), and amelting point of 136.7° C., and a agglomerated polymer was notrecognized.

EXAMPLE 7

[0333] (Chemical treatment of ion-exchange layered silicate)

[0334] In a separable flask, 96% sulfuric acid (750 g) was added to1,130 g of distilled water, and Benclay SL (average particle size 27 μm,300 g) manufactured by Mizusawa Industrial Chemicals, Ltd. as anion-exchange layered silicate (montmorillonite) was added thereto, andthe resultant mixture was reacted at 90° C. for 390 minutes. Thereafter,the reaction product was washed with distilled water to pH 3. The solidobtained was pre-dried at 130° C. for 2 days in a nitrogen stream, andcoarse particles of at least 53 μm were removed, and the product wasfurther dried at 200° C. in a nitrogen stream to obtain 140 g ofchemically treated smectite. The chemically treated smectite thusobtained had a composition of Al: 4.6 wt%, Si: 41.5 wt%, Mg: 0.60 wt%,Fe: 0.9 wt% and Na<0.2 wt%, and Al/Si=0.115 (mol/mol). This catalyst hadan average crushing strength of 8 MPa as measured by a minutecompression tester. This carrier particles had a most frequentlyappearing pore diameter (D_(m)) of 101 Å by nitrogen adsorption methodand a ratio of a pore diameter showing ½ of a peak intensity of the mostfrequently appearing pore diameter (D_(m{fraction (2)})/D_(m)) of 0.83.A pore volume of particles of less than 1,000 Å was 0.43 cm³/g.

[0335] (Preparation of catalyst/prepolymerization catalyst)

[0336] A three-forked flask having a volume of 1 L was substituted withdry nitrogen, and 20 g of the above-obtained chemically treated smectitewas placed therein, and 116 mL of heptane was added thereto to prepare aslurry, and 25 mmol of triethyl aluminum (84 mL of a heptane solutionhaving a concentration of 68 mg/mL) was added thereto, and the resultantmixture was stirred for 1 hour, and the resultant product was washedwith heptane (washing rate: 1/100), and heptane was further added toadjust the total volume to 200 mL.

[0337] Also, in another flask (volume 200 mL),(dimethylsilylenebis(2-methyl-4-(p-chlorophenyl)-4H-azulenyl))zirconiumdichloride (218 mg; 0.3 mmol) was added to heptane containing 3% tolueneto prepare a slurry, and triisobutyl aluminum (3 mmol: 4.26 mL of aheptane solution having a concentration of 145 mg/mL) was added thereto,and the resultant mixture was reacted at room temperature for 60 minuteswhile stirring.

[0338] This solution was introduced into a 1 L flask containing theabove-obtained slurry of chemically treated smectite reacted withtriethyl aluminum, and the resultant mixture was stirred for 1 hour. 213mL of heptane containing 3% of toluene was added to the flask containingthe above slurry, and this slurry was introduced into a 1 L autoclave.

[0339] Into the autoclave, propylene was charged at a feeding rate of 10g/hr at 40° C. for 1 hour, and was then further charged at a feedingrate of 22 g/hr at 50° C. for 3 hours to carry out prepolymerization. Asupernatant liquid of a catalyst slurry obtained was removed bydecantation, and triisobutyl aluminum (12 mmol: 17 mL of a heptanesolution having a concentration of 140 mg/mL) as adeactivation-preventing agent was added to the remaining portion, andthe resultant mixture was stirred for 10 minutes. A solid obtained wasdried at 40° C. for 3 hours under a reduced pressure to obtain 106 g ofa dry prepolymerization catalyst. A prepolymerization magnification (avalue obtained by dividing a prepolymerization polymer amount by a solidcatalyst amount) was 4.30.

[0340] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 24%.

[0341] (Propylene-ethylene random polymerization)

[0342] The same procedure as in Example 1 was repeated, except that theabove-obtained prepolymerization catalyst was used, and 15 g of ethyleneand 34 cc of hydrogen were used. As this result, a catalyst activity was11,600 g-PP/g-catalyst-hour, and an MFR value of 5.9 (dg/min), and theobtained powder had a melting point of 136.2° C. and a bulk density of0.481 g/cc and had satisfactory powder properties.

EXAMPLE 8

[0343] (Propylene-ethylene random polymerization)

[0344] The same procedure as in Example 1 was repeated, except that theprepolymerization catalyst prepared in Example 4 was used and 15 g ofethylene and 34 cc of hydrogen were used. As this result, a catalystactivity was 12,300 g-PP/g-catalyst-hour, and a polymer had an MFR valueof 5.3 (dg/min), a bulk density (BD) of 0.477 (g/cc), and a meltingpoint of 136.0° C., and had satisfactory powder properties.

COMPARATIVE EXAMPLE 1

[0345] (Chemical treatment of ion-exchange layered silicate)

[0346] The same procedure as in Example 1 was repeated, except that1,590 mL of distilled water, 318 g of magnesium sulfate 7 hydrate, 261 gof concentrated sulfuric acid (96%) and 240 g of montmorillonite wereused, and a treating (maintaining) time was 8 hours.

[0347] As this result, the obtained polymers had a most frequentlyappearing pore diameter (D_(m)) of 37 Å by nitrogen adsorption methodand a ratio of a pore diameter showing 1/2 of a peak intensity of themost frequently appearing pore diameter (D_(m½)/D_(m)) of 0.97 (poresize distribution is illustrated in FIG. 3). A pore volume of particlesof less than 1,000 Å was 0.43 cm³/g and a surface area by BET method was326 m^(2 /)g.

[0348] (preparation of catalyst/prepolymerization catalyst)

[0349] The same procedure as in Example 1 was repeated, except that theabove chemically treated silicate was employed. As this result, aprepolymerization catalyst containing 1.71 g of polypropylene per 1 g ofcatalyst was obtained.

[0350] Particles before prepolymerization and particles afterprepolymerization were subjected to fluorescence observation to taketheir photographs, and were compared, and an H value was 91%.

[0351] (Propylene-ethylene random polymerization)

[0352] Polymerization was carried out in the same manner as in Example1, except that the above-obtained prepolymerization catalyst was used.As this result, a catalyst activity was 25,300 g-PP/g-catalyst-hour, anda polymer had a bulk density (BD) of 0.32 (g/cc), an MFR value of 9.3(dg/min), and a melting point of 125.9° C., and a agglomerated polymeramount was 85%. The results are shown in the following Tables 1 and 2.

COMPARATIVE EXAMPLE 2

[0353] (Chemical treatment of ion-exchange layered silicate)

[0354] The same procedure as in Comparative Example 1 was repeated,except that the reaction was carried out at 90° C. for 5 hours. Theproduct was dried at 200° C. in a nitrogen stream to obtain 164 g of achemically treated silicate. The silicate thus obtained had acomposition of Al: 6.74 wt%, Si: 37.0 wt%, Mg: 1.49 wt%, Fe: 1.78 wt%and Na<0.2 wt%, and Al/Si=0.190 (mol/mol).

[0355] This carrier had an average crushing strength of 17 MPa.

[0356] (Preparation of catalyst/prepolymerization catalyst)

[0357] A catalyst slurry before prepolymerization was prepared in thesame manner as in Example7, except that 20 g of the above-preparedchemically treated smectite and 10 mmol of triethyl aluminum wereemployed.

[0358] Also, a solution prepared by reacting triisobutyl aluminum (3mmol: 4.26 mL of a heptane solution having a concentration of 140 mg/mL)with a toluene 87 mL solution ofdimethylsilylenebis(2-methyl-4-(4-chlorophenyl)-4H-azulenyl)zirconiumdichloride (0.3 mmol) was added to the above-prepared slurry.

[0359] The above-prepared catalyst slurry before prepolymerization wasintroduced into a 1 L autoclave, and 210 mL of heptane was addedthereto, and propylene was supplied at 40° C. for 2 hours at a feedingrate of 20 g/hr to carry out prepolymerization. Thereafter, thesupplying of propylene was stopped, and remaining polymerization wascarried out at 40° C. for further 2 hours. After removing a supernatantliquid of the above obtained catalyst slurry, triisobutyl aluminum (12mmol: 17 mL of a heptane solution having a concentration of 140 mg/mL)as a deactivation-preventing agent was added thereto, and the mixturewas stirred for 10 minutes. A solid obtained was dried for 3 hours undera reduced pressure to obtain 31.4 g of a dry prepolymerization catalyst.A prepolymerization magnification (a value obtained by dividing aprepolymerization polymer amount by a solid catalyst amount) was 0.57.

[0360] The above catalyst particles before prepolymerization andcatalyst particles after prepolymerization were subjected tofluorescence observation to take their photographs, and were compared,and an H value was 94%.

[0361] (Propylene-ethylene random polymerization)

[0362] Polymerization of propylene was carried out in the same manner asin Example 6, except that the above catalyst after prepolymerization wasemployed. The powder product thus obtained had a melting point of 134.9°C., and a bulk density of 0.376 g/cc, and its powder properties wereunsatisfactory.

COMPARATIVE EXAMPLE 3

[0363] Chemical treatment of ion-exchange layered silicate)

[0364] 100 g of commercially available montmorillonite (Kunipia F,manufactured by Kunimine Industries Co., Ltd.) pulverized by a jet millwas dispersed in 385 mL of pure water having 133 g of magnesium sulfate7 hydrate and 109 g of sulfuric acid dissolved, and the resultantmixture was reacted at 100° C. for 2 hours, and was cooled to roomtemperature. This slurry was filtrated under a reduced pressure by anapparatus equipped with a Nutsche panel having a diameter of 18 cm andan aspirator connected with a suction bottle. The filtration wasfinished after 1 hour. A cake was recovered and was made into a slurryagain with 3,000 mL of pure water, and washing was repeated 3 times. Thefiltration time was increased in proportion to times of washing, and thefinal filtration took about 3 hours. The final washing liquid (filtrate)had a pH value of 3.47.

[0365] (Granulation of ion-exchange layered silicate)

[0366] The above chemically treated and washed cake solid was made intoa slurry having a concentration of 12 wt% by adding pure water thereto,and the slurry thus prepared was stirred for 1 hour and was subjected tohomogenizer treatment for 10 minutes. A part of the slurry was recoveredto measure a particle size, and the particle size was 5.1 μm. A fractionof particles of less than 1 μm was less than 0.1%.

[0367] The chemically treated montmorillonite slurry wasspray-granulated by a spray-granulating apparatus (L-8) manufactured byOkawara Kakouki K. K. Slurry properties and operation conditions areillustrated below. (Slurry properties: pH=2.84, slurry viscosity=30 CPand density=1.081 g/cc; operation conditions: atomizer rotationnumber=15,000 rpm, supplied liquid amount=0.7 L/hr, inlettemperature=196° C., outlet temperature=130° C. and cyclone pressuredifference=60 mmH₂O)

[0368] As this result, 60 g of granules were recovered. The granulesthus obtained had a bulk density (BD) of 0.46 g/cc and an averageparticle size of 47.0 μm, and an average crushing strength measured byoptionally selecting 10 pieces of sphere-like particles was 1.2 MPa.Also, a pore volume was 0.48 cm³/g.

[0369] (Preparation of catalyst)

[0370] A catalyst was prepared in the same manner as in Example 5,except that 20.0 g of the above-obtained granulated silicate (total porevolume=9.6 cm³) was used and propylene was supplied at a feeding rate of476.2 mmol/hr (constant rate of 20 g/hr) for 120 minutes. As thisresult, 54.68 g of a solid catalyst component was recovered. The solidcatalyst component thus obtained was analyzed, and a prepolymerizedpolypropylene weight amount was 32.3 g.

[0371] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 28%.

[0372] On the other hand, prepolymerization was initiated under the sameconditions as in the above prepolymerization treatment, andprepolymerization reaction was suspended (ethanol was added to purge anunreacted remaining gas) at respective points as shown in Table 6, andpolypropylene amounts formed until the respective points were measured,and polymerization rates at the respective points were calculated. Theresults are shown in the following Table 6.

[0373] It was proved from Table 6 that a polypropylene-forming rate was10 to 17 mg/min per 1 g of silicate during 20 to 30 minutes after theinitiation of feeding propylene, and thereafter the forming rate wasmaintained at a high level of from 6 to 11 mg/min.

[0374] The used silicate had a total pore volume of 9.6 cm³corresponding to 10.7 g of a polypropylene weight amount. Accordingly, atime required for forming a prepolymerized polymer (10.7 g ofpolypropylene) corresponding the total pore volume of the silicate wasabout 50 minutes.

[0375] The prepolymerization pattern is illustrated in FIG. 4.

[0376] (Propylene-ethylene random copolymerization)

[0377] The same procedure as in Example 1 was repeated, except that theabove prepolymerization catalyst was used. As this result, thepropylene-ethylene copolymer thus obtained was 55.0 g. A catalystactivity was 11,000 g-pp/g-catalyst-hour, and a copolymer had a polymerbulk density (BD) of 0.365 (g/cc), an MFR value of 3.41 (dg/min), anethylene content of 3.86 wt% and a melting point of 125.9° C. Theresults are summarized in the following Table 1 and Table 2.

COMPARATIVE EXAMPLE 4

[0378] (Preparation of catalyst)

[0379] A catalyst was prepared in the same manner as in ComparativeExample 2, except that a prepolymerization temperature was 60° C. Asthis result, a catalyst having a prepolymerization magnification (avalue obtained by dividing a prepolymerized polymer amount by a solidcatalyst amount) of 2.07 was obtained.

[0380] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 89%.

[0381] (Propylene-ethylene random copolymerization)

[0382] The same procedure as in Example 1 was repeated, except that theabove prepolymerization catalyst was used. As this result, a catalystactivity was 36,000 g-pp/g-catalyst-hour, and the polymer thus obtainedhad a polymer bulk density (BD) of 0.33 (g/cc), an MFR value of 8.2(dg/min), and a melting point of 127.0° C.

EXAMPLE 9

[0383] (Preparation of catalyst/prepolymerization catalyst)

[0384] The same procedure as in example 2 was repeated, except thatpropylene was supplied at a rate of 100 g/hr for 4 hours at the time ofprepolymerization. As this result, a prepolymerization catalystcontaining 2.25 g of polypropylene per 1 g of a catalyst was obtained.

[0385] Catalyst particles before prepolymerization and catalystparticles after prepolymerization were subjected to fluorescenceobservation to take their photographs, and were compared, and an H valuewas 15%.

[0386] It was proved from Table 6 that a polypropylene-forming rate per1 g of chemically treated montmorillonite was from 1 to 5 mg/min during30 minutes to 1 hour after the initiation of feeding propylene, andthereafter the forming rate was maintained at a low level of from 2 to 3mg/min after 1 hour. Accordingly, a time required for forming aprepolymerized polymer in an amount of corresponding to the total porevolume of the montmorillonite was about 120 minutes. Also, Table 1 showsthat a polymer-forming rate (mg/g-min) indicated a maximum value in theinitial stage of prepolymerization reaction. The prepolymerizationpattern is illustrated in FIG. 4.

[0387] (Propylene-ethylene random polymerization)

[0388] A propylene-ethylene copolymer was continuously produced inaccordance with a process provided with a bulk polymerization tanksystem comprising a liquid phase polymerization tank of an internalvolume of 400 L equipped with a stirrer, a slurry-circulating pump and acirculating line, a degassing system comprising a double tube systemheat exchanger and a flow flash tank, and a screw feeder type drierhaving an inner diameter of 115 mm and a length of 2.0 m and equippedwith a paddle vane having a diameter of 110 mm and also equipped with ajacket in the outside.

[0389] The above prepared prepolymerization catalyst was dispersed inliquid paraffin (Whitelex 335 manufactured by Tonen K. K.) so as to makea concentration of 20 wt%, and a catalyst was introduced in an amount of0.42 g/hr as a catalyst component. Into this reactor, 78 kg/hr of liquidpropylene, 2.4 kg/hr of ethylene, 0.46 g/hr of hydrogen and 56.8 g/hr oftriisobutyl aluminum were continuously supplied, and polymerization wascarried out by maintaining an internal temperature at 65° C. As thisresult, a propylene-ethylene random copolymer having quite satisfactorypowder properties was obtained in an amount of 22.0 kg/hr. A catalystactivity was 52,400 g-pp/g-catalyst, and an activity per 1 hour was40,300 g-pp/g-catalyst-hour.

[0390] The polymer powder thus obtained and the inside of the reactorwere checked, but agglomeration of the polymer powders and deposition oradhesion of the polymer powders onto the reactor were not observed atall. The polymer powder thus obtained had MFR=7.9, Tm=125.1° C. andpolymer BD=0.484 g/cc. The results are summarized in the following Table3.

EXAMPLE 10

[0391] (Propylene-ethylene random copolymerization)

[0392] Polymerization was carried out in the same manner as in Example9, except that 0.84 g/hr of the prepolymerization catalyst as a catalystcomponent, 1.30 kg/hr of ethylene, 0.30 g/hr of hydrogen and 58.0 g/hrof triisobutyl aluminum were supplied and a polymerization temperatureof 70° C. was used, and a propylene-ethylene random copolymer havingexcellent powder properties was obtained in an amount of 23.2 kg/hr. Acatalyst activity was 27,600 g-pp/g-catalyst, and an activity per 1 hourwas 21,200 g-pp/g-catalyst-hour.

[0393] The polymer powder thus obtained and the inside of the reactorwere checked, but agglomeration of the polymer powders and deposition oradhesion of the polymer powders onto the reactor were not observed atall. The polymer powder thus obtained had MFR=7.4, Tm=133.9° C. andpolymer BD=0.489 g/cc. The results are summarized in the following Table3.

EXAMPLE 11

[0394] (1) Chemical treatment of clay mineral

[0395] In a 2 L flask, 200 g of commercially available swellablemontmorillonite (“Benclay SL”, manufactured by Mizusawa IndustrialChemicals, Ltd.) was dispersed in a mixture solution of 1,019 g ofdesalted water, 124 g of 98% sulfuric acid and 96 g of titanium sulfate,and the resultant mixture was stirred at 90° C. for 10 hours. Theresultant product was filtrated and washed with desalted water to pH3.5.

[0396] (2) Drying of clay mineral

[0397] A water-containing solid cake obtained in the above paragraph (1)was pre-dried at 110° C. for 10 hours to obtain titanium salt-treatedmontmorillonite. Among the pre-dried montmorillonite, particles passedthrough a 150 mesh were further dried under a reduced pressure at 200°C. for 2 hours. This carrier had an average crushing strength of 14 MPaas measured by a minute compression tester.

[0398] (3) Organic aluminum compound treatment of salt-treatedmontmorillonite

[0399] 100 g of the dry montmorillonite particles obtained in the aboveparagraph (2) was placed in a 3 L flask under a nitrogen atmosphere, andwas dispersed in 118 mL of n-heptane. Further, 483 mL of a n-heptanesolution of triethyl aluminum (concentration 0.622 mol/L) was addedthereto at room temperature with stirring, and the mixture was reactedfor 1 hour, and the resultant product was subjected to settlingseparation to remove 400 mL of a supernatant liquid. Thereafter, 400 mLof n-heptane was added thereto, and the mixture was stirred for 10minutes, and the resultant product was subjected to settling separationand was subjected to washing steps three times to remove 400 mL of asupernatant liquid.

[0400] (4) Catalyst preparation

[0401] 1.3 L of n-heptane and 12.0 mmol (5.90 g) ofbis(n-butylcyclopentadienyl)hafnium dichloride were dispersed in 2.0 Lof n-heptane in a 10 L reactor equipped with a dielectric stirrer undera nitrogen atmosphere, and the mixture was stirred at 75° C. for 10minutes. Further, 96.0 mmol (10.96 g) of triethyl aluminum was addedthereto, and the resultant mixture was further stirred for 10 minutes.Thereafter, while maintaining the temperature, a slurry dispersion of0.90 L of n-heptane and 100 g of the organic aluminum compound-treatedmontmorillonite obtained in the above paragraph (3) was introduced intothe reactor, and the resultant mixture was stirred for 10 minutes.

[0402] (5) Prepolymerization and drying

[0403] The temperature of the reaction system of the above paragraph (4)was adjusted to 80° C., and an ethylene gas was introduced at a rate of10.0 NL/min for 75 minutes to carry out prepolymerization. The supplyingof ethylene was stopped, and the ethylene gas in the reactor wassubstituted with nitrogen. The above-obtained prepolymerization catalystslurry was washed with n-heptane until the product of a washing ratebecomes 1/8.6. The above-obtained prepolymerization catalyst slurry wasplaced in a 15 L tank type vibrating system vacuum drier equipped with asteam jacket for conducting heat, and 4 L of heptane was then added intothe reactor, and all of the contents remaining in the reactor weretransferred to the drier. After allowing to stand to remove about 5 L ofsupernatant liquid, 56 mmol (11.11 g) of triisobutyl aluminum was addedthereto at room temperature, and 11.2 mmol (5.50 g) of a solid powder ofbis(n-butylcyclopentadienyl)hafnium dichloride was then added thereto,and was dissolved by shaking at 40° C. for 10 minutes. After continuingthe shaking for 10 minutes, the resultant mixture was subjected todrying under a reduced pressure at 70° C. to distill the solvent off.While maintaining the temperature, after visually recognizing that thesolvent was substantially distilled off, drying under a reduced pressurewas carried out for 2 hours, and as this result, 1,016 g of aprepolymerization catalyst powder was recovered.

[0404] (6) Prepolymerization and drying

[0405] 900 g of a prepolymerization catalyst powder obtained in theparagraph (5) was introduced into the reactor of the above paragraph (4)under a nitrogen atmosphere, and was made into a slurry again with 4.2 Lof n-heptane. After adjusting an inner temperature to 75° C., 96.0 mmol(10.96 g) of triethyl aluminum was added thereto and the resultantmixture was stirred for 10 minutes. After adjusting the temperature inthe system to 80° C., an ethylene gas was introduced at a rate of 10.0NL/min for 75 minutes to carry out prepolymerization. The supplying ofethylene was stopped, and the ethylene gas in the reactor wassubstituted with nitrogen. The prepolymerization catalyst slurry thusobtained was placed in the drier used in the above paragraph (5), and 4L of heptane was then added to the reactor to transfer all of thecontents remaining in the reactor into the drier. After allowing tostand to remove about 5 L of a supernatant liquid, drying under areduced pressure was carried out at 70° C. to distill a solvent off.While maintaining the temperature, after visually recognizing that thesolvent was substantially distilled off, drying under a reduced pressurewas carried out for 2 hours, and as this result, 1,851 g of aprepolymerization catalyst powder was recovered.

[0406] (7) Observation of catalyst by fluorescence microscope

[0407] The catalyst particles before prepolymerization of the aboveparagraph (4) and the catalyst particles after prepolymerization of theabove paragraph (6) were subjected to fluorescence observation to taketheir photographs, and were compared, and among the catalyst afterprepolymerization, a proportion of a number of particles having afluorescence density not lower than the fluorescence density of theparticles before prepolymerization (H value) was 3%.

[0408] (8) Ethylene-1-butene copolymerization

[0409] Gas phase copolymerization of ethylene-1-butene was carried outby using the prepolymerization catalyst of the above paragraph (6).Thus, 517 mg/hr of the prepolymerization catalyst powder obtained in theabove paragraph (6), 100 mg/hr of triisobutyl aluminum and 68 mg/hr ofdiethyl aluminum ethoxide were intermittently supplied into a continuoustype gas phase polymerization reactor in which a mixture gas ofethylene, butene and hydrogen (butene/ethylene=1.8%,hydrogen/ethylene=0.038%) is circulated. Polymerization reactionconditions were 90° C., an ethylene partial pressure of 18 kg/cm², anaverage production amount of polymer of 292 g/hr, and an averageretention time of 4.1 hours.

[0410] (9) Blending of additives

[0411] The following antioxidant and neutralizing agent were blendedwith the above obtained ethylene-α-olefin copolymer as additives, andthe blended product was kneaded and granulated by a monoaxial extruderhaving an aperture diameter of 20 mm.

[0412] Anti-oxidant: 1,000 ppm ofoctadecyl-3-(3,5-t-butyl-4-hydroxyphenyl)propionate (Irganox 1076manufactured by Chiba Speciality Chemicals Company); 700 ppm oftetrakis-(2,4-di-butylphenyl)4,4-biphenylene-diphosphite (PEPQmanufactured by Clariant K. K.)

[0413] Neutralizing agent: 300 ppm of calcium stearate (Ca-St (B.K)manufactured by Nitto Kasei Co., Ltd.)

[0414] (10) Film formation and evaluation

[0415] Blown-film molding was carried out under the following operationconditions by using a monoaxial extruder having an aperture diameter of30 mm.

[0416] Screw: aperture diameter 30 mm, L/D=25, full flight type

[0417] Screw rotation number: about 270 rpm

[0418] Dye: spiral mandrel die, aperture diameter 25 mm, lip width 2.0mm

[0419] Resin temperature: 180° C.

[0420] Film size: folding diameter 78 mm, thickness 20 μm

[0421] The film thus obtained was visually observed, and a number offish eyes having a size of a long diameter of at least 0.1 mm wascalculated per 1 g of film was measured to be 7.8 pieces/g. The resultsare summarized in the following Table 4 and Table 5.

COMPARATIVE EXAMPLE 5

[0422] Catalyst observation by a fluorescence microscope,ethylene-1-butene copolymerization, blending of additives, and filmformation and evaluation were carried out in the same manner as inExample 11 (7), (8), (9) and (10) by using the prepolymerizationcatalyst powder obtained in Example 11 (5). The results are summarizedin the following Table 4 and Table 5.

EXAMPLE 12

[0423] (1) Acid treatment of clay mineral 200 g of commerciallyavailable swellable montmorillonite (“Benclay SL”, manufactured byMizusawa Industrial Chemicals, Ltd.) was dispersed in 800 g of 25%sulfuric acid, and the resultant mixture was stirred at 90° C. for 2hours. The resultant product was filtrated and washed with desaltedwater.

[0424] (2) Salt treatment and drying of clay mineral

[0425] All the sulfuric acid-treated montmorillonite cake obtained inthe above paragraph (1) was dispersed in 1,276 g of a commerciallyavailable titanyl sulfate aqueous solution (containing 7.5% of TiO₂ and25.6% of SO₄, manufactured by Sakai Chemical Industry Co., Ltd.), andthe resultant dispersion was stirred at 30° C. for 3 hours. Theresultant product was filtrated and washed with desalted water to pH3.5, and a water-containing solid cake obtained was pre-dried at 110° C.for 10 hours to obtain titanium salt-treated montmorillonite. Among thepre-dried montmorillonite, particles passed through a 150 mesh sievewere further dried under a reduced pressure at 200° C. for 2 hours. Thiscarrier had an average crushing strength of 18 MPa as measured by aminute compression tester.

[0426] (3) Preparation of catalyst

[0427] 2.41 L of n-heptane and a slurry dispersion of 0.90 L ofn-heptane and 100 g of the dry montmorillonite obtained in the aboveparagraph (2) were introduced into a 10 L reactor equipped with adielectric stirrer under a nitrogen atmosphere. A temperature in thesystem was adjusted to 30° C., 24.0 mmol (11.8 g) ofbis(n-butylcyclopentadienyl)hafnium dichloride was dispersed in 0.9 L ofn-heptane, and 96.0 mmol (10.96 g) of triethyl aluminum was immediatelyadded thereto, and the temperature in the system was raised to 40° C.The resultant mixture was further stirred for 60 minutes, and was cooledto 30° C. and was washed with n-heptane until a washing rate of 1/69.

[0428] (4) Prepolymerization

[0429] N-heptane was added to the catalyst slurry obtained in the aboveparagraph (3) to make a liquid amount of 4.21 L, and 96.0 mmol (10.96 g)of triethyl aluminum was added thereto at 30° C., and the temperaturewas immediately raised to 75° C., and the mixture was stirred forfurther 10 minutes. Thereafter, the temperature in the system wasadjusted to 80° C., and an ethylene gas was introduced at a rate of 10.0NL/min for 80 minutes to carry out prepolymerization. The supplying ofethylene was stopped, and the ethylene gas in the reactor wassubstituted with nitrogen.

[0430] (5) Drying of prepolymerization catalyst

[0431] All the prepolymerization catalyst slurry obtained in the aboveparagraph (4) was transferred into a dryer used in Example 11 (5) undera nitrogen atmosphere. 4 L of heptane was added to the reactor, and allthe contents remaining in the reactor were transferred into a drier. Theprepolymerization catalyst slurry transferred into the reactor wasallowed to stand to remove about 5 L of a supernatant liquid, and dryingunder a reduced pressure was carried out at 70° C. to distil a solventoff. While maintaining the temperature, it was visually recognized thatthe solvent was substantially distilled off, and drying under a reducedpressure was then carried out for 2 hours, and as this result, 982 g ofa prepolymerization catalyst powder was recovered.

[0432] (6) Ethylene-1-hexene copolymerization

[0433] Gas phase copolymerization of ethylene and 1-hexene was carriedout by using the prepolymerization catalyst of the above paragraph (5).Thus, 366 mg/hr of the prepolymerization catalyst powder obtained in theabove paragraph (6), 100 mg/hr of triisobutyl aluminum and 68 mg/hr ofdiethyl aluminum ethoxide were intermittently supplied into a continuoustype gas phase polymerization reactor in which a mixture gas ofethylene, hexene and hydrogen (hexene/ethylene=1.2%,hydrogen/ethylene=0.036%) is circulated. Polymerization reactionconditions were 90° C., an ethylene partial pressure of 18 kg/cm , anaverage production amount of polymer of 265 g/hr, and an averageretention time of 4.5 hours

[0434] (7) Evaluation

[0435] Observation of a catalyst by a fluorescence microscope, blendingof additives, film formation and evaluation were carried out in the samemanner as in Example 11 (7), (9) and (10). The results are summarized inthe following Table 4 and Table 5.

COMPARATIVE EXAMPLE 6

[0436] (1) Preparation of catalyst

[0437] 2.41 L of n-heptane and a slurry dispersion of 0.90 L ofn-heptane and 100 g of the dry montmorillonite obtained in Example 12(2) were introduced into a 10 L reactor equipped with a dielectricstirrer under a nitrogen atmosphere. The temperature in the system wasadjusted to 30° C., and 24.0 mmol (11.8 g) ofbis(n-butylcyclopentadienyl)hafnium dichloride was dispersed in 0.9 Q ofn-heptane, and 96.0 mmol (10.96 g) of triethyl aluminum was immediatelyadded thereto, and the temperature in the system was raised to 75° C.,and the resultant mixture was stirred for further 10 minutes.

[0438] (2) Prepolymerization

[0439] The temperature in the system of the above paragraph (1) wasadjusted to 80° C., an ethylene gas was introduced at a rate of 10.0NL/min for 80 minutes to carry out prepolymerization. The supplying ofethylene was stopped, and the ethylene gas in the reactor wassubstituted with nitrogen. The temperature in the system was cooled to30° C., and the resultant product was washed with n-heptane until awashing rate of 1/69. Drying of the prepolymerization catalyst wascarried out in the same manner as in Example 12 (5) to recover 783 g ofa prepolymerization catalyst powder.

[0440] (3) Evaluation

[0441] Ethylene-1-hexene copolymerization, observation of a catalyst bya fluorescence microscope, blending of additives, film formation andevaluation were carried out in the same manner as in Example 12 (6) andExample 11 (7), (9) and (10). The results are summarized in thefollowing Table 4 and Table 5. TABLE 1 Maximum 1/2 peak Intensity PoreAverage Acid Polymer- Prepolymerization Polymer- pore pore diameter Porecrushing concent- forming homogenization forming diameter diameter ratiovolume strength ration rate index rate D_(m) (Å) D_(m1/2) (Å)D_(m1/2)/D_(m) (cm³/g) (MPa) N (mg/g · min) H value (mg/g · min) Ex. 1101 77 0.76 0.42 13 10.6 7 25 7 Ex. 2 101 83 0.82 0.44 11 10.6 5 12 5Ex. 3 101 83 0.82 0.44 11 10.6 5 12 5 Ex. 4 101 84 0.83 0.43 8 10.6 7 287 Ex. 5 90 68 0.76 0.42 7.6 10.6 7 29 7 Ex. 6 101 83 0.82 0.44 11 10.6 512 5 Ex. 7 101 84 0.83 0.43 8 10.6 7 24 7 Ex. 8 101 84 0.83 0.43 8 10.67 28 7 Comp. 37 36 0.97 0.43 17 3.1 7 91 7 Ex. 1 Comp. 39 37 0.95 0.3817 3.1 17 94 17 Ex. 2 Comp. 39 33 0.85 0.48 1.2 3.1 17 45 17 Ex. 3 Comp.39 37 0.95 0.38 17 3.1 17 89 17 Ex. 4 Ex. 9 101 83 0.82 0.44 11 10.6 515 5 Ex. 10 101 83 0.82 0.44 11 10.6 5 15 5

[0442] TABLE 2 Prepolymerization Catalyst homogenization activity MFRAgglomerate index g-PP/ dg/ Tm BD d amount H value g-cat.hr min ° C.g/cc wt % Ex. 1 25 35600 8.5 126.8 0.450 0.8 Ex. 2 12 52100 8.1 125.70.475 2.5 Ex. 3 12 48500 1.6 121.7 0.483 0.9 Ex. 4 28 40500 6.1 125.90.484 1.2 Ex. 5 29 34000 10.8 126.5 0.441 1.5 Ex. 6 12 22000 6.8 136.70.483 <0.5 Ex. 7 24 11600 5.9 136.2 0.481 <0.5 Ex. 8 28 12300 5.3 136.00.477 <0.5 Comp. 89 25300 9.3 125.9 0.320 85 Ex. 1 Comp. 94 12500 4.8134.9 0.376 <0.5 Ex. 2 Comp. 45 11000 3.4 125.9 0.365 5.7 Ex. 3 Comp. 8936000 8.2 127.0 0.330 83 Ex. 4

[0443] TABLE 3 Catalyst Catalyst Production activity MFR amount amountg-PP/ Activity dg/ Tm BD g/hr kg/hr g-cat.hr g-PP/g-cat min ° C. g/ccEx. 9 0.42 22.0 52400 40300 7.9 125.1 0.484 Ex. 10 0.84 23.2 27600 212007.4 133.9 0.489

[0444] TABLE 4 Maximum Pore Average peak pore 1/2 Intensity diameterPore crushing diameter pore diameter ratio volume strength D_(m) (Å)D_(m1/2) (Å) D_(m1/2)/D_(m) (g/cm³) (MPa) Ex. 11 72 55 0.76 0.34 14 Ex.12 75 58 0.77 0.35 18 Comp. 72 55 0.76 0.34 14 Ex. 5 Comp. 75 58 0.770.35 18 Ex. 6

[0445] TABLE 5 polymerization Catalyst result Physical properties ofproduct H value BD Activity MFR Density BD FE (%) (g/cm³) (g-PE/g-[B])(g/10 min) (g/cm³) (g/cm³) (pieces/g) Ex. 11 3 0.390 11800 1.4 0.9250.456 7.8 Ex. 12 17 0.411 7100 1.3 0.934 0.477 15.0 Comp. 61 0.339 124001.2 0.923 0.439 18.0 Ex. 5 Comp. 67 0.355 9950 1.3 0.934 0.446 62.4 Ex.6

[0446] TABLE 6 Example 5 Comparative Example 3 Example 9 PolymerizationPolymerized Polymerization Polymerized Polymerization PolymerizedPolymerization time amount rate amount rate amount rate Min. g mg/g ·min g mg/g · min g mg/g · min 0 0.00 0.0 0.00 0.0 0.00 0.0 5 10 0.00 1.81.66 6.8 0.00 0.0 15 20 0.17 2.6 2.60 11.7 25 30 1.67 7.0 3.33 16.7 0.500.8 40 0.96 4.7 50 0.86 4.2 60 2.16 3.6 5.97 8.1 0.57 2.8 70 74 80 900.92 1.5 4.37 5.7 1.50 2.4 120 0.96 1.6 6.86 10.9 2.05 3.3 150 1.72 2.91.02 4.4 5.23 8.5 155 1.00 4.3 180 0.29 0.5 3.75 5.6 8.45 13.8 210 1.220.2 2.56 4.0 7.08 11.5 240 1.00 1.7 0.81 1.3 244 6.12 8.8 270 274 1.403.4 280 13.21 13.0 300 10.85 27.1 304 0.67 1.1 330 4.36 7.3 360 4.31 7.2

INDUSTRIAL APPLICABILITY (EFFECT OF THE INVENTION)

[0447] According to the present invention, a polymer having excellentparticle properties can be obtained at a high activity and at a lowcost. Particularly, in the production of a low melting point polymerwhich has been considered to be difficult because of causing fouling,agglomeration of polymer particles and adhesion or deposition of apolymer to a reactor can be prevented in the present invention. Also,since a bulk density of a polymer is improved, a continuous stableoperation can be easily made on an industrial scale, and productivitycan be improved.

[0448] Also, the present invention solves such problems that finepowders are produced since catalyst particles and polymer particleseasily collapse in case of particles having a too low carrier strength,and also solves such problems that fine powders are produced sincegrowth of particles is non-uniform in prepolymerization in case ofparticles having a too high carrier strength and that unpulverizedcarrier nuclei remained in catalyst particles produce fish eyes and gelswhich make an outer appearance of a product poor.

[0449] Further, by using a catalyst component or a catalyst of thepresent invention, it is possible to produce a low melting point polymerefficiently and stably even at a higher polymerization temperature thanin conventional cases.

[0450] The entire disclosures of Japanese Patent Application No.2000-277640 filed on Sep.13, 2000, Japanese Patent Application No.2001-075412 filed on Mar. 16, 2001 and Japanese Patent Application No.2001-109549 filed on Apr. 9, 2001 including specifications, claims,drawings and summaries are incorporated herein by reference in itsentirety.

1. A catalyst component for olefin polymerization, which comprises anion-exchange layered silicate having the following features 1 and 2:feature 1: in a pore size distribution curve calculated from desorptionisotherm by nitrogen adsorption-desorption method, a pore diameter Dmshowing a maximum peak intensity D_(VM) is from 60 to 200 Å; and feature2: in a pore size distribution curve calculated from desorption isothermby nitrogen adsorption-desorption method, a pore diameter D_(m½)(Å) onthe smaller pore size side corresponding to a ½ peak intensity of themaximum peak intensity D_(VM) has a relation of D_(m½)/D_(m) of at least0.65 and less than 1, provided that the largest value is employed whenthere are a plurality of D_(m½)values.
 2. The catalyst component forolefin polymerization according to claim 1, the ion-exchange layeredsilicate further has the following feature 3: feature 3: theion-exchange layered silicate has an average crushing strength of atleast 3 MPa as measured by a minute compression tester.
 3. The catalystcomponent for olefin polymerization according to claim 1 or 2, whereinthe ion-exchange layered silicate is treated with an organic aluminumcompound having an alkyl group having at least 4 carbon atoms.
 4. Thecatalyst component for olefin polymerization according to any one ofclaims 1 to 3, wherein the ion-exchange layered silicate is obtained bythe following steps 1 and 2: step 1: after granulating, the ion-exchangelayered silicate is treated with an acid having an acid concentration(N) satisfying the following formula (I), N≧6.0   (Formula I) whereinthe acid concentration N is expressed by acid mol number×acid valencenumber/acid aqueous solution volume (unit: liter); and step 2: after theabove step 1, the ion-exchange layered silicate is treated with anorganic aluminum compound having an alkyl group having at least 4 carbonatoms.
 5. The catalyst component for olefin polymerization according toany one of claims 1 to 4, wherein the ion-exchange layered silicate is asmectite group silicate.
 6. A catalyst for olefin polymerization havingthe following features 3 and 4, which is formed into a prepolymerizationcatalyst by contacting a metallocene catalyst supported on anion-exchange layered silicate with olefin: feature 3: the ion-exchangelayered silicate has an average crushing strength of at least 3 MPa asmeasured by a minute compression tester; and feature 4: aprepolymerization homogenization index (H-Value) obtained fromfluorescent observation results of each of catalyst particles beforeprepolymerization and after the prepolymerization is at most 60%.
 7. Thecatalyst for olefin polymerization according to claim 6, wherein anion-exchange layered silicate as defined in claims 1 to 5 is used.
 8. Acatalyst for olefin polymerization, which is a prepolymerizationcatalyst obtained by contacting a metallocene catalyst supported on anion-exchange layered silicate with olefin, wherein (b) a polymer-formingrate is maintained at most 10 mg/min per 1 g of the ion-exchange layeredsilicate (a) until a prepolymerization polymer is formed in an amountcorresponding to a pore volume of the ion-exchange layered silicate. 9.A catalyst for olefin polymerization which is a prepolymerizationcatalyst obtained by contacting a metallocene catalyst supported on anion-exchange layered silicate as defined in claim 1 with olefin, wherein(b) a polymer-forming rate is maintained at most 10 mg/min per 1 g ofthe ion-exchange layered silicate (a) until a prepolymerization polymeris formed in an amount corresponding to a pore volume of theion-exchange layered silicate.
 10. A catalyst for olefin polymerization,which is a prepolymerization catalyst obtained by contacting ametallocene catalyst supported on an ion-exchange layered silicate asdefined in claim 1 with olefin, wherein (a) a new metallocene complexand (b) an organic aluminum compound optionally used are contacted with(c) a metallocene catalyst supported on the ion-exchange layeredsilicate, provided that the metallocene complex (a) may be the same ordifferent from the metallocene complex already supported.
 11. A catalystfor olefin polymerization, which is a prepolymerization catalystobtained by contacting a metallocene catalyst supported on anion-exchange layered silicate as defined in claim 1 with olefin, wherein(a) the ion-exchange layered silicate is contacted with a metallocenecomplex for at least 30 minutes, (b) a material obtained by the abovecontact operation (a) is washed with a slurry of a liquefied α-olefin orinner inert hydrocarbon solvent, and (c) olefin prepolymerization iscarried out by using a material obtained by the above washing operation(b).
 12. A process for producing polyolefin, which comprisespolymerizing olefin by using a catalyst comprising a metallocenecompound and a catalyst component for olefin polymerization as definedin claim
 1. 13. A process for producing polyolefin, which comprisespolymerizing olefin by using a catalyst for olefin polymerization asdefined in claim
 6. 14. A process for producing polyolefin, whichcomprises polymerizing olefin by using a catalyst for olefinpolymerization as defined in claim 8.